用所给词的适当形式填空。

1. The       (invent) of a space rocket took many years.

2. We must improve the       (able) of speaking English greatly.

3. We should lay the        (found) for our joy in the future.

4. For         (century) this has been their custom.

5. Learning English well must have        (science) ways.

6. She decided that she taught        (she) Japanese.

7. The little boy looked         (curious) at the tall young man.

食管口线虫寄生于宿主的（）

A．结肠 

B．气管 

C．表皮内 

D．皮肤表面 

E．毛囊和皮脂腺中