Listen! There must be someone _________ through the jungle.
A. trek B. treking C. trekking
The ____ of some wild animals reminds us __ the problems on environment.
| A．loss, of | B．lose, of | C．loss, that | D．lost, to |
He devoted as much time as he could _________ on the plan.
| A．working | B．to work | C．worked | D．to working |
---He's seldom late for school,______?
---_____. He is used to going to school early.
| A．is he, No | B．has he, No | C．isn’t he, Yes | D．hasn’t he, Yes |
—What did your father ask you?
—He asked me ___________.
| A．whom I was chatting with | B．where am I with my friends |
| C．when would I go home | D．if I have finished my homework |
He was last seen _________in his office at about 7:15 p.m..
| A．work | B．working | C．to work | D．worked |