If nothing________，the oceans will turn into fish deserts.
| A．does | B．had been done |
| C．will do | D．is done |
The work he devoted his time to _____ worth praising.
| A．was | B．be |
| C．being | D．been |
The theory he sticks to ______ to be of no use in our studies.
| A．proves | B．prove |
| C．proving | D．be proved |
The man you referred to _____ just now.
| A．comes | B．come |
| C．coming | D．came |
——You didn’t wait for Mr. Black last night, did you?
——No, but we ____. He didn’t return home at all.
| A．couldn’t have | B．needn’t have |
| C．didn’t need to | D．should wait have |
A terrible earthquake happened in that district at the end of 2004, ____ many countries in the world paid close attention to this.
| A．where | B．when | C．which | D．what |