General English Level 4 Version 2.1 © 2004 acl Pty Ltd GELEV4 Unit 02 Topic 04.doc If you don't concentrate, it's easy to fall off the wall. conditional clause main clause + present simple tense. the belay helps to stop your fall. If + the present simple tense If you come off the rock, + present continuous tense. you are not concentrating. + the present continuous tense. she's working too hard. If + the present continuous tense If she is feeling tired, + the present simple tense. she takes a rest. When we start a conditional sentence with the conditional (if) clause we need to use a comma to separate the two clauses. We can also start the zero conditional with the main clause. Main clause Conditional clause The belay helps to stop your fall. if you come off the rock. He is telling the truth. if he says he is scared. When we start the sentence with the main clause, we don't need to use a comma. Comparing the zero conditional and the first conditional We use the zero conditional to talk about facts or things which are generally true. If one event happens then another event generally follows. In the zero conditional, the verbs in the main clause and the conditional clause are in the present tense. We use the first conditional to talk about events in the future. It is possible the event will happen but it depends on another event or action. In the first conditional, the verb in the main clause is in the future tense and the verb in the conditional clause is in the present simple tense. If I save enough money, I'll go on a holiday. This is the first conditional. I might go on a holiday. It depends on how much money I save. We'll miss the bus if we don't hurry. This is the first conditional. We might catch the bus. It depends on what time we leave. 70