—Why does the River smell terrible?
—Because large quantities of water .
| A．have polluted | B．have been polluted |
| C．has been polluted | D．is being polluted |
—You didn’t invite Mary to the ball?
—____ her, too?
| A．Must I invite | B．Should I have invited |
| C．Must I have invited | D．Should I invite |
—She joined a football team last fall and was recently made captain.
—Never _____ she'd ever have that much energy.
| A．I had thought | B．I would have thought |
| C．could I have thought | D．will I have thought |
I ____ you, but I didn’t think you would listen to me.
| A．could have told | B．must have told | C．should tell | D．might rell |
—The research on the new bird flu virus vaccine is challenging and demanding. Who do you think can do the job?
—____ my students have a try?
| A．Shall | B．Will | C．Could | D．Should |
His failure in the exam suggested that he __________ the teacher’s instructions.
| A．can’t have followed | B．needn’t have followed |
| C．mustn’t have followed | D．shouldn’t have followed |