— Can you imagine what is Jack doing now? He is playing football outside while everyone else is busy in class!
— He his homework, I think.
| A．must have finished | B．must finish | C．can’t have finished | D．mustn’t have finished |
Experiments of this kind ________ in both the U.S. and Europe long before the Second World War.
| A．conducted | B．was conducted |
| C．had been conducted | D．had conducted |
-- Shall we take a taxi there since time is limited?
-- ________. It should be hard to get one during the rush hour.
| A．Go ahead | B．Don’t mention it |
| C．No doubt | D．Just forget it |
Traveling without ordering rooms in advance can eat up precious vacation time ________luck is smiling on you.
| A．unless | B．as | C．if | D．when |
-- It’s more convenient to take a subway than drive a private car.
-- ________. What’s more, it’s also a good way to support the low-carbon lifestyle.
| A．Quite so | B．So is it |
| C．By all means | D．All right |
It is known to all that the US is about the same size as China, whereas its population is five times________.
| A．as few | B．fewer |
| C．as little | D．smaller |