Conditional sentences (إذا، إنْ، لو)

Three particles, two situations

English uses one word, "if", and shifts the tense to show how likely something is. Arabic keeps the tense flat and chooses a different particle instead.

After إِذَا and إِنْ the past tense does not mean past time: إِذَا دَرَسْتَ is about the future.

إذا: the everyday conditional

The workhorse. Both verbs stand in the past, and the sentence points forward.

• إِذَا دَرَسْتَ نَجَحْتَ. — If you study, you will succeed.
• إِذَا نَزَلَ الْمَطَرُ بَقِينَا فِي الْبَيْتِ. — If it rains, we will stay at home.
• إِذَا وَصَلْتُ مُبَكِّرًا اتَّصَلْتُ بِكَ. — If I arrive early, I will call you.

إنْ: the formal conditional

إِنْ belongs to careful written Arabic and to proverbs. It puts both verbs in the jussive, which for sound verbs means a sukun on the end.

• إِنْ تَدْرُسْ تَنْجَحْ. — If you study, you will succeed.
• إِنْ تَسْأَلْ تَعْرِفْ. — If you ask, you will find out.

The past tense works after إِنْ as well: إِنْ دَرَسْتَ نَجَحْتَ.

لو: the unreal conditional

لَوْ says that the condition is not true. Both verbs are past, and the result clause carries a لـ on its verb. This one لـ is what English expresses with "would".

• لَوْ كَانَ عِنْدِي وَقْتٌ لَسَافَرْتُ. — If I had time, I would travel.
• لَوْ دَرَسْتَ لَنَجَحْتَ. — If you had studied, you would have succeeded.
• لَوْ عَرَفْتُ عُنْوَانَهُ لَزُرْتُهُ. — If I knew his address, I would visit him.

Arabic does not distinguish "if I had time" from "if I had had time" by tense; context decides. For a past state, كَانَ makes it explicit: لَوْ كُنْتُ أَعْرِفُ لَأَخْبَرْتُكَ. — If I had known, I would have told you.

لَوْلَا takes a noun and means "if it were not for": لَوْلَا الْمَطَرُ لَخَرَجْنَا. — If it were not for the rain, we would have gone out.

When the result needs فـ

If the result clause is not a plain past verb (or, after إِنْ, a jussive), it must start with فـ. That covers a nominal sentence, an imperative, a future with سـ, and a negation with لَنْ or مَا.

• إِذَا وَصَلَ أَحْمَدُ فَأَخْبِرْنِي. — If Ahmad arrives, tell me.
• إِذَا دَرَسْتَ فَسَتَنْجَحُ. — If you study, you will succeed.
• إِذَا لَمْ تَأْتِ فَالْأَمْرُ صَعْبٌ. — If you do not come, the matter is difficult.

Watch out as an English speaker

• A past-tense verb after إِذَا is about the future. ✗ إِذَا تَدْرُسُ نَجَحْتَ. / ✓ إِذَا دَرَسْتَ نَجَحْتَ.
• English "if" covers both real and unreal; Arabic does not. Do not use لَوْ for something that may well happen. ✗ لَوْ دَرَسْتَ نَجَحْتَ for a real plan / ✓ إِذَا دَرَسْتَ نَجَحْتَ.
• There is no word for "would". The result of لَوْ is a past-tense verb, normally with لـ in front of it, and never a future. ✗ لَوْ كَانَ عِنْدِي وَقْتٌ سَوْفَ أُسَافِرُ. / ✓ لَوْ كَانَ عِنْدِي وَقْتٌ لَسَافَرْتُ.
• An imperative or a nominal result needs فـ. ✗ إِذَا وَصَلَ أَخْبِرْنِي. / ✓ إِذَا وَصَلَ فَأَخْبِرْنِي.

Example dialogue

هَلْ سَتَأْتِي غَدًا؟ — Will you come tomorrow?
إِذَا انْتَهَيْتُ مِنَ الْعَمَلِ مُبَكِّرًا حَضَرْتُ. — If I finish work early, I will come.
وَإِذَا لَمْ تَنْتَهِ؟ — And if you do not finish?
فَسَأَتَّصِلُ بِكَ. لَوْ كَانَ عِنْدِي وَقْتٌ أَكْثَرُ لَبَقِيتُ مَعَكُمْ كُلَّ الْمَسَاءِ. — Then I will call you. If I had more time, I would stay with you all evening.
إِذَا وَصَلْتَ فَاتَّصِلْ بِي مِنَ الْبَابِ. — If you arrive, call me from the door.