—Hi, Linda. Could you climb the Yuelu Mountain with me this weekend?
—Sorry, I ________. I have to climb the homework mountain at home.
A.must B.couldn't C.can't
Changsha is a happy city ________ you will never want to leave once you come.
A.which B.where C.what
—More and more people like buying things online?
—Yes. Because the price is ________ than that of things in real shops.
A.lower B.much cheaper C.far cheaper
— You look pale. Are you sick?
— Yes. I don't feel well. My sister was sick several days ago and I am afraid she________me her cold.
A.was giving B.will give C.has given
— What's the thing with three legs?
— It's a cup. It________drinking wine in ancient times.
A.was used to B.was used for C.used to
Those plants in the yard will not die________you take good care of them.
A.until B.unless C.if