—Must we keep the window _______ all the time?
—No, you don’t have to.
| A．opening | B．opened | C．to open | D．Open |
There are so many beautiful clothes in the store. I really don’t know _____.
| A．what to choose | B．how to choose |
| C．when to choose | D．which to choose |
We all know the _____ of learning English well.
| A．important | B．importance |
| C．different | D．difficult |
The room must _____ up right now. It’s too dirty.
| A．be cleaned | B．be cleaning |
| C．clean | D．cleaned |
, the rain stopped when we went out for a walk.
| A．Lucky | B．Luck | C．Luckily | D．Luckless |
The old man lived but he didn’t feel .
| A．alone; lonely | B．alone; alone |
| C．lonely; alone | D．lonely; lonely |