Experiments of this kind __________ in both the U. S. and Europe well before the Second World War.
| A．have conducted |
| B．have been conducted |
| C．had conducted |
| D．had been conducted |
—Your boss looks rather a kind person.
—But in fact he is cold and hard on us. You ______ believe it!
| A．shouldn’t | B．mustn’t | C．wouldn’t | D．needn’t |
There are other matters which I don’t propose to ______ at the moment.
| A．go up | B．go around | C．go for | D．go about |
One evening, I was with my friend Auguste Dupin at his house in Paris when he had a visit _____ Georges Godinot, head of the Paris Police.
| A．at | B．from | C．to | D．with |
. When he ______ the door, he found his keys were nowhere.
| A．would open | B．was to open | C．had opened | D．opened |
—Putting on a happy face not only helps us make friends but also makes us feel better.
—______.
| A．I’m with you on that | B．I’d love to | C．It’s up to you | D．It’s my pleasure |