1 . The reason ________ he gave for his absence is ________ he was drunk.

2 . — I’ll ask the teacher about the attributive clause. I’m very puzzled about it.
— That’s just __________ most of our classmates have doubt.

3 . He didn’t finish his homework on time. That is________ he was punished by the teacher. （用适当的词填空）

4 . The problem is ________ we can get the things we need. (用适当的词填空)

5 . Have you found the red mark(记号) on the map? This is ________ Huashan High School lies.

6 . A ship in harbor is safe, but that is not________ ships are built for. (用适当的词填空)

7 . Go and get your coat. It is ______ you left it.

8 . The reason why he failed is __________ he was too careless.

9 . —I prefer shutting myself in and listening to music all day on Sundays.
—That's ________ I don't agree. You should have a more active life.

10 . Part of the reason Charles Dickens loved his own novel, David Copperfield, was ________ it was rather closely modeled on his own life.