用所给的正确形式填空。

1. He ___­­­­________ ever ___________ (be) to the History Museum several times.

2. — _______________ you ever _____________ (be) to the zoo?

—Yes. I ________ (go) there last summer. I _______ (see) many kinds of animals there.

3. —Where is Mr. Wang?

—He _________ (go) to the library. He wants to borrow some library books.

4. Rodgers ______ (plant) those trees. He _______ (do) it the day before yesterday.

5. We ______ (learn) English for more than two years.

6. When he ____________(finish) his work, he ____________(ring) me up.