if引导的条件状语从句

if引导的条件状语从句

含有if引导的条件状语从句的复合句表示假如有从句动作的发生，就会有主句动作的发生。

★通常情况下，如果主句用一般将来时，if引导的条件状语从句用一般现在时。如：

If he misses the last bus, he'll have to walk home.

We'll have a party in the garden if the weather is good.

★如果主句是祈使句或者主句的谓语部分含有情态动词，if引导的条件状语从句也常用一般现在时。如：

If anyone calls, tell them I'm very busy.

If it rains, you can stay at home and relax.

【链接】

本单元我们还学了连词unless，可意为“除非；如果不”，通常可以和if ... not 互换使用。如：

He won't go to sleep unless you tell him a story.

=He won't go to sleep if you don't tell him a story.

【运用】

含有if和unless引导的条件状语从句的复合句

Ⅰ. 句型转换

1. You will be in the museum. Don't talk loudly.

(用if合并为含有条件状语从句的复合句，且从句在前)

___________________________________________

2. You will take more exercise next year. You will keep healthy.

(用if合并为含有条件状语从句的复合句，且从句在后)

___________________________________________

3. You will work hard. You won't do well in your exam.

(用unless合并为含有条件状语从句的复合句，且从句在前)

___________________________________________

4. Mary will be busy this afternoon. She will play with us.

(用unless合并为含有条件状语从句的复合句，且从句在后)

___________________________________________

5. You can't go into the art club unless you are a student.

(改为同义句)

You can't go into the art club __________________.

Ⅱ. 单项选择

1.—Thank you for telling me so much knowledge (知识) about nature.

—Don't mention it. __________ you have more questions, come to me any time.

A. If

B. Because

C. Though (2018 四川乐山)

2.—The weather report says that it __________ tomorrow in most parts of Anshun city.

—If it __________, the school sports meet will be canceled (将被取消).

A. will rain; will rain

B. will rain; rains

C. rains; will rain

D. rains; rains (2018 贵州安顺)

3. If I __________ a two-week holiday next year, I will take part in a short study tour (旅行) to Beijing University.

A. took

B. take

C. will take

D. are taking (2018 湖北黄石)

4. You mustn't drive a car on the road __________ you get a driver's license (驾照).

A. unless

B. if

C. since (2018 湖南长沙)

5. The pollution in the river is terrible! It will be cleaner _______ we take action (采取措施) now.

A. though

B. if

C. unless

D. until

6. Mandy will work out the math problem __________ she gives up.

A. if

B. because

C. so

D. unless

答案

Ⅰ. 1. If you are in the museum, don't talk loudly.

2. You will keep healthy if you take more exercise next year.

3. Unless you work hard, you won't do well in your exam.