Mrs. Green always helps her mother even though going to work _________most of her day.
| A．takes out | B．takes down | C．takes up | D．takes off |
I have been living in the United States for twenty years, but seldom _____ so lonely as now．
| A．have I felt | B．I had felt | C．I have felt | D．had I felt |
In the study of modern science, there are many cases _____ soldiers can teach officers．
| A．when | B．who | C．which | D．where |
— Why didn’t they complete the task in time?
— Because it was not until late afternoon _____ they began to solve the major problem．
| A．when | B．that | C．before | D．which |
Your story is perfect; I’ve never heard _____ before．
| A．a better one | B．the better one | C．the best one | D．a good one |
We have a wide selection of sweaters that will appeal _____ all ages, and in particular the teenager market．
| A．for | B．in | C．to | D．on |