—I hear Johnson ______ in the middle school.
—What? I can’t imagine him ______ as a teacher.
| A．teach；to work |
| B．teaches；working |
| C．teaches；to work |
| D．teach；working |
It is reported that in our country cities ________ heavy air pollution that is 30 percent above the national standard or higher should try to meet standards by 2030.
| A．suffering | B．suffer | C．suffered | D．are suffering |
It's ten years since the scientist _______to discover the valuable chemical.
| A．kept up | B．set out | C．took in | D．set about |
I called Bruce many times yesterday, but I couldn’t get through. His brother ____ on the phone all the time.
| A．was to talk | B．was talking | C．would be talking | D．had talked |
Although Fleming discovered Penicillin, it was over a decade ______ someone else turned it into the great drug of the 20th century.
| A．before | B．since | C．when | D．as |
—Look! Here is a message on my mobile phone, asking me to send money to....
—Don’t believe it! It’s a trick. More than one person _____ by such tricks so far.
| A．had been cheated | B．was cheated | C．have been cheated | D．has been cheated |