21．--- How long are you staying?
--- I don’t know. .
A．That’s OK B．Never mind C．It depends D．It doesn’t matter
22．The conference had been held to discuss the effects of tourism the wildlife in the area.
A．in B．on C．at D．with
23．You are not in good health, I think. You could improve your by running every day.
A．position B．situation C．energy D．condition
24．At first, the company had 15 notebook computers but only one – third used regularly. Now we have over 60 working all day long.
A．were B．are C．was D．is
