He came back late, _____ which time all the guesses had already left.
| A．by | B．at | C．during | D．after |
I can ______ be a teacher. I’m not a very patient person.
| A．seldom | B．ever | C．never | D．always |
When he _______ the door, he found his keys were nowhere.
| A．would open | B．opened | C．had opened | D．was to open |
Most Americans would prefer to keep their problems ______ themselves, and solve their problems ______ themselves.
| A．to; by | B．by; to | C．for; to | D．in; on |
Every evening after dinner, if not______ from work, I will spend some time walking my dog.
| A．being tired | B．tiring | C．tired | D．to be tired |
Nine in ten parents said there were significant differences in their approach to educating their children compared with __ of their parents.
| A．those | B．one | C．both | D．that |