Mary is so wet. She _______ in the rain.
| A．must be caught | B．must have been caught |
| C．should have been caught | D．can have been caught |
.It is the first time the students ________ to Hyde Park.
| A．have gone | B．have been gone |
| C．had gone | D．had been gone |
.Bicycles made in China are cheaper than ________ made in Japan, but almost as good in quality.
| A．ones | B．it | C．that | D．those |
While working in the countryside , the students ________ a great deal of knowledge on plant life.
| A．looked up | B．picked up | C．put up | D．called up |
By the time she ________ tomorrow, the work ________.
| A．arrives ; will be finished |
| B．arrives ; will have been finished |
| C．will arrive ; will have been finished |
| D．arrives ; will have finished |
Some people waste a lot of food ________ others haven’t enough to eat.
| A．however | B．when | C．as | D．while |