Have you ever had the case _______ you can’t recognize your friend’s voice on the phone?
| A．which | B．that | C．where | D．when |
This factory produced much dirty water, which resulted in a wide _______ of environmental problems.
| A．branch | B．range |
| C．species | D．wave |
Please tell me how the accident _______. I am still in the dark.
| A．came up | B．came out |
| C．came to | D．came about |
It is______ of him to set his aim high but do little, so he is always leaving things undone.
| A．specific | B．typical |
| C．flexible | D．widespread |
— Do you think it's a good idea to make friends with your students?
—________, I do. I think it's a great idea.
| A．Really | B．Hopefully |
| C．Actually | D．Eventually |
Mary couldn’t________ the terrible working conditions in that factory and resigned last week.
| A．catch up with | B．keep up with |
| C．put up with | D．come up with |