1 . ---- Do you know the reason ______ he was late for the meeting yesterday?
----Yes, but I don’t think the reason ______he told me is reasonable. (用适当的词填空)

2 . I don’t know the reason ________ David has refused to see me . (用适当的词填空)

3 . I don’t know the reason _______you were absent from the meeting , but I’m sure that someone will tell me the reason ________ you haven’t told me.(用适当的词填空)

4 . Do you know the reason _______ Mr. Smith didn’t come ? (用适当的词填空)

5 . Jack never keeps the books in a place _________ he can find them easily. That’s the reason _______ he’s always looking for them. (用适当的词填空)

6 . Sadly, ____________________ the number of monarch butterflies is falling.   
不幸的是，人类活动是黑脉金斑蝶数量下降的主要原因。

8 . The reason _____ I love western music is that it has inspired me a lot when I am in difficulty.(用适当的词填空)

9 . The reason ________ I’m here to tell the story is that I made the right decision. (用适当的词填空)

10 . There are many reasons _________ people like travelling.

A．that

B．where

C．why

D．when