if条件从句（讲义）通用版英语六年级下册

小升初英语语法专项：if条件从句 if条件句：条件句用于陈述语气，表示假设的情况可能发生，其中 if 是“如果”的意思。 用 法 例 句 ① 主句为一般将来时态，if从句用一般现在时态（即主将从现）。 We will stay at home if it rains tomorrow. 如果明天下雨，我将要呆在家。 ② 主句中含有情态动词，if从句用一般现在时态。 If you finish your homework, you can go home now. 如果你做完了作业，你现在可以回家了。 ④ 主句为过去将来时，if从句用一般过去时态（如果涉及到be 动词，一律都用were）。此时，表达的是和现实相反的推测，用虚拟语气。 If I were you, I wouldn’t do it like that. 如果我是你，我就不会那么做的。 If you gave me some money, I would be very happy. 如果你给我一些钱，我就会很高兴的。 (1)条件状语从句通常由连词if引导，意为“如果、假如”，主句不能 用be going to表示将来，而应该用shall，will。 If you leave now, you are never going to regret it. (错误) If you leave now, you will never regret it. (正确) (2)if “如果”，引导条件状语从句，主句用一般将来时，从句则用 一般现在时，如： If it rains tomorrow, I shan’t climb the hills. (3)另外，主句是祈使句或含有情态动词，从句也用一般现在时。如： Please call me if he comes next Sunday. Can you call the policeman if you are in the trouble. 注意 宾语从句中的if与条件状语从句if的区别。宾语从句中的if“是 否”相当于 whether，引导宾语从句，时态需根据语境确定。如果主句用 一般现在时，从句可以根据具体情况选用时态，如果主句用一般过去 时，从句必须用过去式的某种形式。 I don't know if it will rain tomorrow. 我不知道明天是否会下雨。 Our teacher said there was going to be a football match the next month. 我们说下月将有场足球比赛。 同步练习 一．用括号内所给词的正确形式填空。 1. What will you buy if you ________（have）a lot of money? 2. If it ________（not snow）tomorrow, we will feel unhappy. 3. You mustn’t go to school if you ________（be）still in bed. 4. If he _______（be）at home at that time, he would know it. 5. Please show me the way if you ________（know）it. 6. You will hurt your teeth if you ________（eat）too much candy. 7. If you gave me a toy car, I _________（be）very happy. 8. I would get the prize if I _________（work）hard. 9．If she ______ (finish ) work early ,she ______(go) home. 10．If the weather______（be）fine，we_______(go)for a walk . 11. If I_____(have) time tonight ,I _______(finish) the book I’m reading. 12. If it ______(rain) next weekend , we_______(not be able to ) plant the vegetable . 13. If it_______(rain),we______(stay) at home . 14.If she______(arrive) ,she _____(phone) me . 15. I