Air pollution is getting more and more serious, so we must take action it is too late.
| A．before | B．after | C．until | D．when |
I don’t believe the reason____he has given for not coming to the lecture.
| A．why | B．that | C．how | D．what |
In the forest we observed some trees____the leaves were black with disease.
| A．where | B．of which | C．in which | D．whose |
I often think of the years ____ I worked with the foreigners, ____ has had a great
effectonmylaterlife.
| A．that;which | B．when;which | C．which;that | D．when;who |
He expressed his hope ____ he would visit Chinaagain thenext year, and this was
The very hope____he expressed as soon as he arrived in the country.
| A．that;that | B．which;which | C．that;which | D．which;that |
.____has finished the task ahead of time will be rewarded,though we don’t know who
It will be.
| A．Those who | B．Anyone | C．Whoever | D．Who |