英语条件句

条件句条件句是有“条件状语分句+主句”构成的复杂句。请看以下四种类型的条件句：1. If you heat ice, it melts.2. If we catch the 10 o’clock train, we shall (will, can, may) get there by lunch-time.3. If we caught the 10 o’clock train, we would (could, might) get there by lunch-time.4. If we had caught the 10 o’clock train, we would (could, might) have got there by lunch-time. 请问，这四种类型的区别在哪？第一种类型条件句 真实条件句的一种 whenever条件句a). 表示普遍真理和客观事实1. If you pour oil on water, it floats.2. 如果温度降到0度，水会结冰。b). 表示现在习惯动作1. If I make a promise, I keep it.2. 假如你去看电影，你会更喜欢看哪种电影？3. 假如现在下雨，我就坐车去上班。c). 表示过去习惯动作1. If it rained, I went to work by car.2. If I made a promise, I kept it.3. 过去我要是饿了的话，我通常都会大吃一顿。回答以下问题：Example: What happens if we heat ice? If we heat ice, it melts.1. What happens to water if the temperature rises to 100 degrees centigrade?2. How many days are there in February if it is a leap year?3. What happens if flowers don’t get any water?4. Who do businessmen go to see if they want to borrow money?5. What do you expect a teacher to do if you make a mistake?6. What do we get if we mix red with yellow?7. What kind of music did you prefer if you went to a concert?第二种类型条件句 真实条件句主体If it is fine tomorrow, we can have a picnic somewhere.If you wake up before me, give me a call.If we should miss the 10 o’clock train, we shan’t get there till after lunch.从句不管主语的人称和数如何，一律用should+不定式，主句动词可根据语义意图采用不同形式。Should 仅表示一种不太肯定的委婉口气，并不影响条件的真实性。If he should fail to come, ask Philip to work in his place.If he should come tomorrow, I would tell him everything.如果再下雨的话，花就会开。Set your alarm clock, and you won’t oversleep.= If you set your alarm clock, you won’t oversleep.Set your alarm clock, or (else) you’ll oversleep.