. We should learn how to value what we have ______ it is too late.
| A．when | B．after | C．before | D．until |
—Johnthis week?
—No. He’s on holiday.
| A．Does, work | B．Did work | C．Has, worked | D．Is, working |
Silver is the best conductor of electricity, copperit closely.
| A．followed | B．to follow | C．following | D．being followed |
Mr. White works as a lawyer now, but hein a company for several years.
| A．worked | B．has worked | C．had worked | D．has been working |
I’m no painter, and to me, one painting is much like.
| A．the other | B．others | C．another | D．one |
Be tough-minded, but tender-hearted, ?
| A．isn’t it | B．are you | C．aren’t you | D．will you |