—What do you do, Rita？
—I’m a clerk in a foreign company now．But I _____ English in a high school for 10 years．
A．teach B．have taught
C．taught D．am teaching
—How are you getting along with your German, Kate？
—Oh, Mr．Black, I’m so tired of it．Maybe I should drop out _____ it kills me．
A．when B．after C．while D．before
A public health campaign _____ the number of heart disease deaths by 80 percent over the past three decades．
A．had reduced B．had been reduced
C．has reduced D．has been reduced
If it _____ earlier, the printing machine would not have broken down．
A．has been repaired B．is repaired
C．had been repaired D．was repaired
—Congratulations！I hear you’ve won the first prize in the singing competition．—You _____ be mistaken．I’m in the dance class．
A．must B．may C．should D．could
She doesn’t speak our language, _____ she seems to understand what we say．
A．for B．and C．yet D．or
