Mr. Green is said________an experiment to prove their new method of solving the problem when young.
| A．to do |
| B．to have done |
| C．to be doing |
| D．to have been doing |
I admire Stephen Hawking greatly，whose________about black holes has a great effect on astronomy.
| A．theory | B．practice |
| C．way | D．method |
The new traffic rules that took effect on January 1 are much stricter than________in the past.
| A．that | B．this |
| C．it | D．those |
It’s really a small world！I________we would meet here.
| A．don’t think | B．haven’t thought |
| C．didn’t think | D．won’t think |
It is shown that men have________as women do on average while driving according to recent statistics.
| A．twice as many serious accidents |
| B．serious accidents as twice many |
| C．twice serious accidents as many |
| D．serious accidents as many twice |
________is well known to everyone，I should say，is that a man becomes learned by asking questions.
| A．Who | B．It |
| C．As | D．What |