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18. Should you arrive at the office earlier than I do, please turn on the air-conditioner.
19. If it weren't snowy, the children would go to school.
20. Had he not died so young, he would be a fmous musician by now.
21. Unless you tell me the whole truth, I won't help you.
22. Were you to take good care of the car, it wouldn't break down so often.
Câu đk loại 1 : If S Vs/es, S will (not) V
Câu đk loại 2 : If S V2/ed, S would (not) V
Câu đk loại 3 : If S had (not) V3/ed, S would (not) have V3/ed
Đảo ngữ đk loại 1 : Should S V, S will (not) V
Đảo ngữ đk loại 2 với động từ thường : Were S to V, S would (not) V
Đảo ngữ đk loại 3 : Had S V3/ed, S would have V3/ed
Câu đk hỗn hợp : If S had V3/ed, S would V
Unless ~ If not

18.if you arrive at the office earlier than i do, please turn on the air-conditioner. =>should...you arrive at the office earlier than i do, please turn on the air-conditioner...... 19.the children don't go to scholl in the snowy weather. =>if it....weren't snowy ,the children would go to scholl.... 20.he died so young; oterwise, he would be a famous musician by now. =>had.....he died so young,he would have been a famous musician by now...... 21 .you must tell me the whole truth or i won't help you =>unless......you tell me the whole truth , i won't help you..... 22.the car breaks down so often because you don't take gook care of it. => were you to take gook care of it.the car wouldn't break down so often,.........