.
I looked down into the river and could see Old Tom _____ by the boat.
| A．swims | B．swam | C．to swim | D．swimming |
How did it ________ that the ancient building was burnt down in an hour?
| A．happen | B．occur | C．take place | D．come about |
—An ant has two stomachs—one for itself, one for others.
—Really? Quite interesting. I ________ anything about it.
| A．don't know | B．have known | C．haven't known | D．didn't know |
Noise is unpleasant, ________ when you are trying to sleep.
| A．especially | B．specially | C．extremely | D．naturally |
—Was ________ problem solved?
—We were trying to think of ________ way out, but it was difficult to find one.
| A．a; a | B．a; the | C．the; a | D．the; the |
The couple have decided to________buying a car until their economic condition becomes much better.
| A．hold off | B．hold on | C．hold up | D．hold back ． |