I was on the highway _______ this car went past followed by a police car. They ______ at least 150 kilometers an hour.
| A．when; should have been driving |
| B．while; would have driven |
| C．as; could have driven |
| D．when; must have been driving |
Early peoples moved around, ______ the herds of animals.
| A．having followed | B．followed |
| C．following | D．to follow |
______ takes a lot of concentration and a great sense of balance to stay on it.
| A．It | B．This | C．What | D．That |
The questionnaire takes ______ ten to fifteen minutes to complete and can be used along with the assessment interview.
| A．mainly | B．punctually | C．approximately | D．precisely |
—Where is Mother?
—She is in the kitchen. She ______the housework all morning.
| A． does | B．has been doing | C．has done | D．was doing |
Not knowing how to grow crops，the primitive people had no ______ but to gather the fruit and hunt animals for food.
| A．conception | B．command | C．virtue | D．alternative |