In short

Everything you have written so far has been one event per sentence. This lesson bolts two together: “when I arrived, I found…”, “before the manager gets here”, “because the weather is cold”. Arabic does that with a small closed set of connectors - عِنْدَما، بَيْنَما، قَبْلَ أَنْ، بَعْدَ أَنْ، مُنْذُ، لِأَنَّ، بِسَبَبِ and a few more - and the whole difficulty is not their meanings, which are easy, but what each one is legally allowed to be followed by. Some demand a past verb, some demand المُضارِعُ المَنْصوبُ from lesson 33, and some refuse a verb altogether and insist on a noun in the genitive.

So learn each connector as a two-part chunk: the word plus its complement. قَبْلَ أَنْ is not “before”, it is “before + a subjunctive verb, always, even in a sentence about last Tuesday”. بِسَبَبِ is not “because”, it is “because of + a noun”. The reason half of the lesson is where English speakers lose the most marks, because English lets “because” and “because of” swap places with a little rewriting and Arabic does not: لِأَنَّ takes a clause and puts its subject into the accusative, بِسَبَبِ takes a bare noun, and لِذٰلِكَ turns the sentence round and announces the result instead.

The rule

1. Three possible complements. Every connector in this lesson takes one or two of exactly three things: a full verbal clause (normally a ماضٍ), أَنْ + المُضارِعُ المَنْصوبُ, or a noun in الجَرّ (usually a مَصْدَر). Once you know which slot a connector opens, you cannot go wrong; almost every learner error here is pouring the wrong complement into the right word.

2. عِنْدَما and حينَما - the everyday “when”. For one completed past event they take a ماضٍ: عِنْدَما وَصَلْتُ إِلَى البَيْتِ، وَجَدْتُ رِسالَةً. For a habit or a general truth they take a مُضارِع: حينَما أَشْعُرُ بِالتَّعَبِ أَشْرَبُ القَهْوَةَ. The two words are interchangeable; حينَما is a shade more formal and commoner in writing. Neither of them ever takes أَنْ - عِنْدَما already is the linker - and عِنْدَما is one word, never written عِنْدَ ما. Either clause may come first; when the time clause opens the sentence, modern writing usually puts a «،» after it.

3. لَمّا - the narrative “when”. Same job as عِنْدَما but restricted: ماضٍ in the clause and ماضٍ in the main sentence, and it belongs to storytelling rather than to conversation. لَمّا سَمِعَ الخَبَرَ صَمَتَ طَويلًا. Be aware of a homograph: a different لَمّا means “not yet” and is followed by المَجْزوم (لَمّا يَصِلْ), which belongs to the negation system, not here. The word shape is identical; only the mood of the verb behind it and the sense tell them apart.

4. بَيْنَما - “while”, and it wants كانَ. بَيْنَما heads a whole clause, never a bare noun, and because “while” needs a background action that was already running, that clause is normally كانَ + مُضارِع (lesson 32): بَيْنَما كُنْتُ أَقْرَأُ الجَريدَةَ، رَنَّ الهاتِفُ. It can also head a nominal sentence: بَيْنَما هُوَ في الطَّريقِ، اتَّصَلَ بِهِ صَديقُهُ. A second, very common use is contrast - “whereas”: هُوَ يُفَضِّلُ الشّايَ بَيْنَما أُفَضِّلُ أَنا القَهْوَةَ. Never *بَيْنَما الدَّرْسِ and never *بَيْنَما أَنْ.

5. كُلَّما - “whenever”, past + past. This one looks wrong to an English eye and is worth memorizing as a fixed frame: كُلَّما + ماضٍ … ماضٍ, even though the meaning is habitual and timeless. كُلَّما زارَني جَدّي فَرِحْتُ. The same frame carries the “the more…, the more…” comparison: كُلَّما زادَ العَمَلُ زادَ التَّعَبُ. Do not confuse it with the two-word كُلُّ ما “everything that”, which is a quantifier plus a relative pronoun (lesson 39): كُلُّ ما قالَهُ صَحيحٌ.

6. قَبْلَ أَنْ - always المُضارِعُ المَنْصوبُ. This is the rule of the lesson. Whatever the tense of the main sentence, the verb after قَبْلَ أَنْ is a subjunctive: خَرَجْتُ مِنَ المَكْتَبِ قَبْلَ أَنْ يَصِلَ المُديرُ - past main verb, subjunctive after قَبْلَ أَنْ. The logic is sound once you see it: at the moment of the first event the “before” event had not happened yet, so Arabic marks it as unrealized. Modern Arabic keeps to the subjunctive here, so *قَبْلَ أَنْ يَصِلُ with the indicative ḍamma is simply wrong, and *قَبْلَ أَنْ وَصَلَ - a shape a few classical writers did use - is not one to copy.

7. بَعْدَ أَنْ - ماضٍ or مَنْصوب, and the timeline chooses. If the whole sentence is in the past, use a ماضٍ: بَعْدَ أَنْ أَنْهَيْتُ واجِبي، شاهَدْتُ فيلْمًا. If the event is still ahead, use المَنْصوب: سَنَخْرُجُ بَعْدَ أَنْ نَتَناوَلَ الفَطورَ. Unlike قَبْلَ أَنْ, this one genuinely has two options, and picking the one that matches the main verb will always be idiomatic.

8. The مَصْدَر shortcut: قَبْلَ / بَعْدَ + a genitive noun. Instead of a clause you can put a verbal noun straight after قَبْلَ or بَعْدَ: قَبْلَ الوُصولِ “before arriving”, بَعْدَ الدَّرْسِ “after the lesson”. قَبْلَ and بَعْدَ are ظَرْفانِ مَنْصوبانِ heading an إِضافَة, so whatever follows them is مَجْرور - that kasra is not optional. To name the subject, attach a pronoun to the مَصْدَر: قَبْلَ خُروجِهِ “before he goes out”, بَعْدَ وُصولِنا “after we arrived”. This shape is shorter, extremely common in writing, and safe whenever the subject is obvious; the full account of the مَصْدَر is lesson 54.

9. مُنْذُ - “since” and “for”. With a noun it means either a starting point or a stretch of time, and the noun is مَجْرور: مُنْذُ الصَّباحِ، مُنْذُ سَنَتَيْنِ. With a clause it takes أَنْ + ماضٍ: مُنْذُ أَنْ تَعَلَّمْتُ السِّباحَةَ. The main verb is then usually a plain مُضارِع, because the situation is still going on - أَدْرُسُ العَرَبِيَّةَ مُنْذُ سَنَتَيْنِ is “I have been studying Arabic for two years”. Arabic has no separate “have been” tense; مُنْذُ carries that meaning by itself. مُذْ is a lighter twin of the same word.

10. حَتّى - “until”, and the mood tells you whether it happened. Lesson 33 promised this split. A ماضٍ after حَتّى reports something that really did take place: انْتَظَرْنا في المَحَطَّةِ حَتّى وَصَلَ القِطارُ. A مَنْصوب after حَتّى points at something still ahead, wanted or expected: سَأَنْتَظِرُ هُنا حَتّى يَعودَ أَخي. حَتّى also works as a plain preposition with a noun in the genitive - العَمَلُ مُسْتَمِرٌّ حَتّى المَساءِ - and, in a completely different job, as the particle “even”. Context separates them without trouble.

11. فَوْرَ - “as soon as”, noun only. فَوْرَ is a ظَرْف standing in an إِضافَة, so it must be followed by a noun, normally a مَصْدَر with an attached pronoun: فَوْرَ وُصولِهِ اتَّصَلَ بِنا “as soon as he arrived he called us”. A verb may never follow it directly. If you want a clause with a full verb, the ready-made equivalents are حالَما + ماضٍ or بِمُجَرَّدِ أَنْ + verb.

12. لِأَنَّ - “because” + a clause, subject in the accusative. لِأَنَّ is لِـ plus أَنَّ, and أَنَّ forces the noun behind it into النَّصْب while its predicate stays مَرْفوع: لِأَنَّ الطَّقْسَ بارِدٌ - الطَّقْسَ accusative, بارِدٌ nominative. The predicate can itself be a verb: لِأَنَّ الطَّقْسَ تَغَيَّرَ فَجْأَةً. When the subject is a pronoun it does not stand as a separate word; it attaches: لِأَنَّهُ مَريضٌ، لِأَنَّني نَسيتُ. So لِأَنَّ can never be followed immediately by a verb - “because I forgot” has to become “because-I I-forgot”. The rest of the أَنَّ family, and the difference between أَنْ and أَنَّ, is lesson 44.

13. بِسَبَبِ - “because of” + a noun. بِسَبَبِ is بِـ plus سَبَب in an إِضافَة, so what follows it is a genitive noun: تَأَخَّرَتِ الحافِلَةُ بِسَبَبِ الازْدِحامِ. You will also meet بِسَبَبِ أَنَّهُ … in the press - the أَنَّ clause is read as a مَصْدَر مُؤَوَّل, so the إِضافَة is not broken - but it is heavy, and most editors rebuild such a sentence with لِأَنَّهُ. Two relatives worth recognizing: نَظَرًا لِـ, a formal “owing to”, and بِفَضْلِ, “thanks to”, normally kept for good outcomes.

14. لِذٰلِكَ - the same link run backwards. لِأَنَّ and بِسَبَبِ put the cause second; لِذٰلِكَ puts it first and announces the result: المَطْعَمُ مُغْلَقٌ اليَوْمَ، لِذٰلِكَ سَنَأْكُلُ في البَيْتِ. Any cause-and-effect pair can be said in all three shapes, and choosing between them is a matter of what you want to foreground, not of grammar.

15. What is deliberately left out. The “when” that is really an “if” - إِذا - is a conditional and waits for lesson 56, and the unreal لَوْ and لَوْلا for lesson 65. The other way of saying “while”, hanging an accusative circumstantial clause on the sentence (خَرَجَ وَهُوَ يَبْتَسِمُ), is الحالُ, lesson 55. إِنَّ and its sisters as a system are lesson 44, and the connectors that stitch whole paragraphs together are lesson 66.

Forms & patterns

The ten time connectors with the complement each one opens. This table is the lesson in one screen.

قَبْلَ and بَعْدَ each have two shapes for the same meaning. The right-hand column is the shorter one and needs no mood decisions at all.

لِأَنَّ with an attached pronoun subject. The duals لِأَنَّكُما، لِأَنَّهُما and the feminine plural لِأَنَّكُنَّ are built the same way and are left out to keep the table readable.

One cause, three sentences. Note where the accusative and the genitive fall.

Examples

Common mistakes

• قَبْلَ أَنْ يَصِلُ -> قَبْلَ أَنْ يَصِلَ - أَنْ always puts the verb into المَنْصوب, so the final ḍamma has to become a fatḥa. This is the single commonest slip in the lesson.
• خَرَجْتُ قَبْلَ أَنْ وَصَلَ المُديرُ -> خَرَجْتُ قَبْلَ أَنْ يَصِلَ المُديرُ - a past main verb does not drag the قَبْلَ أَنْ clause into the past. That clause is unrealized by definition and stays subjunctive.
• عِنْدَما أَنْ وَصَلْتُ -> عِنْدَما وَصَلْتُ - عِنْدَما is already the whole connector. Adding أَنْ is like saying “when that I arrived”.
• بَيْنَما أَقْرَأُ، رَنَّ الهاتِفُ -> بَيْنَما كُنْتُ أَقْرَأُ، رَنَّ الهاتِفُ - “while” needs a background that was already running, and that is كانَ + مُضارِع. A bare مُضارِع reads as a present habit.
• كُلَّما أَزورُهُ أَفْرَحُ -> كُلَّما زُرْتُهُ فَرِحْتُ - كُلَّما is a past + past frame even when the meaning is a repeated habit. Do not translate the English present.
• لِأَنَّ الطَّقْسُ بارِدٌ -> لِأَنَّ الطَّقْسَ بارِدٌ - أَنَّ takes its noun in النَّصْب. The predicate بارِدٌ keeps the ḍamma; only the subject moves.
• لِأَنَّ هُوَ مَريضٌ -> لِأَنَّهُ مَريضٌ - a pronoun subject after أَنَّ can only be an attached one. The independent pronouns of lesson 6 are impossible in this slot.
• لِأَنَّ نَسيتُ المِفْتاحَ -> لِأَنَّني نَسيتُ المِفْتاحَ - a verb may never come straight after لِأَنَّ. Attach the pronoun first, then put the verb.
• بِسَبَبِ أَنَّهُ مَريضٌ -> لِأَنَّهُ مَريضٌ - بِسَبَبِ is built for a plain noun. When what follows is a whole sentence, the word to reach for is لِأَنَّ.
• فَوْرَ وَصَلَ إِلَى المَطارِ -> فَوْرَ وُصولِهِ إِلَى المَطارِ - فَوْرَ needs a مَصْدَر, never a verb. For a full verb clause, switch to حالَما وَصَلَ.

Tips

• Store each connector as word + complement, never as a bare gloss. “قَبْلَ أَنْ + مَنْصوب” is one item to memorize; “before” is a translation that will get the ending wrong.
• The escape hatch when you are unsure of the mood: use the مَصْدَر. قَبْلَ الوُصولِ and بَعْدَ الاجْتِماعِ have no verb at all, so nothing can be misconjugated - and they sound more written, not less.
• Use the English shape to pick the reason word: if you can say “because of” and a noun follows, it is بِسَبَبِ; if a whole sentence follows, it is لِأَنَّ. This test almost never fails.
• Say the accusative after لِأَنَّ out loud - لِأَنَّ الطَّقْسَ - until it feels automatic. It is audible in careful speech, so it is one of the few case endings that will actually be noticed.
• Watch the kasra after مُنْذُ and بِسَبَبِ: مُنْذُ سَنَةٍ، بِسَبَبِ المَطَرِ. Both are genitive slots, so a tanwīn ḍamma there is an immediate giveaway.
• Pair بَيْنَما with كانَ as a reflex, the way you pair لَنْ with the subjunctive. If a بَيْنَما clause has no كانَ, check whether you really meant “whereas”.
• Do not chase إِذا yet. It looks like another “when”, but it is a conditional with its own machinery, and meeting it now will only blur the ten connectors you have here.