牛津上海英语九年级上册 Unit5Grammar(共21张PPT)

We use if sentences to talk about possible actions and the results of these actions. An if sentence has two parts. Each part is called a clause. Each clause contains a verb. If you stick a pin into a balloon, it bursts. We use if sentences to talk about results that will certainly happen. In these sentences, both verbs are in the present simple tense. If you cool water, it turns into ice. If you boil water, it becomes steam. The if clause talks about the possible action. The second clause talks about the result that will certainly happen. Water becomes steam if you boil it. In if sentences, the if clause can come first or second. When the if clause comes first, there is always a comma after it, e.g., If you cool water, it turns into ice. Water turns into ice if you cool it. Read these if sentences and match the possible actions with the results. A1 Work in pairs. Read the dialogue below and make similar dialogues about the other sentences in A1. A2 S1 What happens if