He set off down the main street. He _____.
| A．ran | B．walked |
| C．rode | D．started his journey |
The Sanlu Milk Powder event is a clear indication that food safety is a big problem; nobody can ___ all foods are secure to us, but we are sure that the situation is turning for the better．
| A．acknowledge | B．guarantee | C．identity | D．clarify |
—I am going to travel to America．Would you consider telling me about your experiences there?
—__．Let's discuss it over dinner．
| A．That's all right | B．Go ahead |
| C．By all means | D．It just depends |
I don't think the experiment is ___ failure, because it has provided us with ___valuable experience for our future tests.
| A．不填; 不填 | B．不填; a | C．a; a | D．a; 不填 |
---I’m sorry! I would have taken him to hospital if I had known he was seriously ill.
--- But ______ .
| A．you didn't | B．you hadn't | C．he wasn't | D．you aren't |
Rock-climbing is a breathtaking activity, very popular nationwide among young people, ______ cooperation as well as courage plays an important role.
| A．who | B．which | C．where | D．of which |