They ___________to put their hearts into study..
| A．have made their minds | B．have made their mind |
| C．have made up their minds | D．have made up their mind |
I felt surprised that anyone of his intelligence ________ such an easy test.
| A．might have failed | B．could have failed |
| C．should have failed | D．must have failed |
We ________ take clean drinking water for granted. One day we may run out of it.
| A．needn't | B．can't |
| C．won't | D．shouldn't |
Parents are doing all they ________ to help their children achieve their ambitions.
| A．shall | B．can |
| C．may | D．need |
________ for the fact that she broke her leg, she might have passed the exam.
| A．Hadn't it been | B．Had it not been |
| C．Was it not | D．Were it not |
His pale face suggested he ________ angry and I suggested that he ________ at once.
| A．should be; should leave | B．was; left |
| C．was; leave | D．be; left |