Tham khảo tài liệu 'oxford guide to english grammar part 50', ngoại ngữ, ngữ pháp tiếng anh phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | PAGE 337 257 Verbs in conditional sentences d As well as the past simple we can use the continuous or could. If the sun was shining everything would be perfect. Ifl could help you I would but I m afraid I can t. As well as would we can use other modal verbs such as could or might in the main clause. IfI had a light I could see what I m doing. Ifwe could roll the car down the hill we might be able to start it. e We can use would in the if-clause for a request. If you wouldn t mind holding the line I ll try to put you through. Sometimes there is no main clause. Ifyou djust sign here please. We can also use would like. If you d like to see the exhibition it would be nice to go together. 5 Open conditions in the past a We can use the past tense for an open condition in the past. Perhaps Mike took a taxi. Well if he took a taxi he ought to be here by now. I used to live near the library. IfI wanted a book I went and got one I would go and get one. b We can use a Type 2 pattern as the past of a Type 1. Type 1 Don t go. If you accept the invitation you will regret it. Type 2 I told you that if you accepted the invitation you would regret it. And now you are regretting it aren tyou c We can combine a past condition with a future result. If they posted the parcelyesterday it won t get here before Friday. 6 Type 3 conditionals a The pattern is if. past perfect. would perfect. Ifyou had taken a taxi you would have got here in time. If I d phoned to renew the books I wouldn t have had to pay a fine. The man would have died if the ambulance hadn t arrived so quickly. We d have gone to the talk if we d known about it. We would have gone if we had known. Here the past perfect refers to something unreal an imaginary past action. Ifyou had taken a taxi means that you didn t take one. We cannot use the past simple or perfect in the main clause. NOT Ifyou had taken a taxi you got hadgot here in time. NOTE Would have or had have is not used in the if-clause except in very informal .