时态填空。

1. Listen! Someone _______ (sing) in the next room.

2. There _______ (be) an exhibition of art in the museum tomorrow.

3. Everyone in our class _______ (enjoy) music very much.

4. It's so cloudy. I think it _______ (rain).

5. We are looking forward to _______ (go) sightseeing.

6. When is the best time _______ (visit) your hometown?

7. The thief tried _______ (run) away but the policemen _______ (catch) them in the end.

8. Is it difficult _______ (finish) _______ (write) the article in one day?

石英质玉可分为（）。

A.微晶质类

B.微晶质类，显晶质类

C.隐晶质类，显晶质类

D.微晶质类，隐晶质类，显晶质类