--- How long are you staying?
--- I don’t know. .
| A．That’s OK | B．Never mind | C．It depends | D．It doesn’t matter |
To keep healthy, Professor Johnson ____ cycling as a regular form of exercise after he retired.
| A．made up | B．put up | C．took up | D．carried out |
Tough ______ _money, his parents managed to to send him to a key university.
| A．lacked | B．lacking of | C．lacking | D．lacked in |
She ____________ the path as the trees around her became thicker.
| A．lost sight of | B．caught sight of | C．lost sight | D．caught sight |
Once ________ more attention, the little trees could have grown better.
| A．given | B．to give | C．giving | D．having given |
After ten hours’ operation, the doctors managed to _____the one-year-old twins at the head.
| A．isolate | B．separate | C．divide | D．remove |