31. You see the lightning _____ it happens, but you hear the thunder later.
| A．for an instant | B．on the instant | C．in a instant | D．the instant |
____ the TV play, he got down to ____ his homework.
| A．Watching; do | B．After his watching; do |
| C．Watched; doing | D．Having watched; doing |
—Will you go skiing with me this winter vacation?
--- It __________________.
| A．all depend. | B．all depends. | C．is all depended | D．is all depending |
I lost my way. I wonder ________ I can turn in the dark.
| A．who | B．whom | C．to whom | D．for whom |
—Do you mind if I keep pets in the building?
--- _________________.
| A．I’d rather you didn’t actually. | B．Of course not, it’s not allowed here. |
| C．Great! I love pets. | D．No, you can’t. |
The fire ______ at might was still seen ______ the next morning.
| A．breaking out; burning | B．to break out; to burn |
| C．broke out; burnt | D．had broken out; burning |