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.