Tham khảo tài liệu 'oxford learner's grammar 9', ngoại ngữ, ngữ pháp tiếng anh phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Conditional sentences 243 Introduction A Most Conditional sentences have a sub-clause starting with the word if. We can use many different verb forms in conditional sentences. Here are some real examples. If you haven t got television you can t watch it. If you go to one of the agencies they have a lot of temporary jobs. If someone else has requested the book you would have to give it back. If you lived on the planet Mercury you would have four birthdays in a single Earth year. In genera we use verb forms in conditional sentences in the same way as in other kinds of sentences. If you ve finished work for today you can go home. Compare You ve finished work for today so you can go home. In an open condition when something may or may not happen we use the present tense if you go to one of the agencies. When we talk about something unreal we often use the past tense if you lived on the planet Mercury. After an unreal condition wc use would in the main clause you would have four birthdays. B here are some verb forms which often go together. These patterns are usually called Types 1 2 and 3. Type 1 If the company fails we will lose our money. 24 1 Type 2 If the company failed we would lose our money. 246 Type 3 If the company had failed we would have lost our money. 247 There is another pattern which we can call Type 0. Type 0 If the company fails we lose our money. 244 c The if-clause usually comes before the main clause but it can come after it If you re in a hurry you needn t wait for me. You. needn t wait for me if you re in a hurry. A comma between the clauses is more likely when the if-clause comes first and less likely when it comes at the end. 343 Conditional sentences D We can use conditional sentences in a number of different ways not only to give information but also for example when we request advise criticize and so on. Use Example Requesting If you re going into town could you post this letter for me please Advising If your headache persists you should see