1. you are tired, you had better have a rest.
2. —Why do you like English?
— it's so interesting.
3. he is busy, I won't trouble him.
4. The man has become one of the most famous dancers a dancing programme.
5. you are wrong, you should say sorry.
6. —Why did you call Sarah last night?
— I wanted to invite her to my birthday party this weekend.
7. We didn't attend the meeting yesterday it was rainy.
8. the heavy rain, we had to stay inside.
9. it was Saturday, he didn't have to go to school.
10. the weather is fine, let's go for a picnic.
11. I came back late yesterday I was on duty.
12. everyone is here, let's begin the discussion.
13. you know it, I won't repeat it.
14. He didn't hear the knock at the door he was listening to the radio.
15. —Why didn't you come to our picnic?
— my father didn't let me leave my home.

1. As/Since 2. Because 3. Since/As 4. because of 5. Since/As 6. Because 7. because 8. Because of 9. Since/As 10. Since/As 11. because 12. Since/As 13. Since/As 14. because 15. Because

()1.(2024·江苏镇江一模)—It is said that the famous snack smelly tofu in Changsha tastes strange!
—______ we have been here, why not give it a try?
A.Since
B.When
C.If
D.Though

1. A 【点拨】since 既然；when 当……时；if 如果；though 虽然。根据“why not give it a try”可知，此处意为“既然我们在这里，为什么不试试呢”，应用 since 引导原因状语从句。故选 A。

()2.—Why didn't you come back to the meeting?
—______ I didn't think the meeting would be interesting.

A.As
B.Since
C.For
D.Because

2. D 【点拨】because 意为“因为”，常用来回答 why 引导的特殊疑问句。故选 D。