一个教师可讲授多门课程，一门课程可由多个教师讲授。则实体教师和课程间的联系是

A．1:1联系

B．1:m联系

C．m:1联系

D．m:n联系

用括号中所给词的适当形式填空。

1.Tom is much ______ than Sam. (cool )

2. My hair is a little ______ than hers. (short)

3. Pedro is ______ than Paul. (funny)

4. Li Ping is a little ______ than me. (outgoing)

5. Which is ______ in China, tea or coffee? (popular)

6. Tina is much ______ than Tara. (athletic)

7. Liu Li is a little ______ than her sister. (quiet)

8. Ruth is ______ than any other girl in my class. (serious)

9. Java has ______ hair than Mary. (curly)

10. Paul is ______ than Pedro. (thin)