Weather experts advise us out if PM2.5 levels are above 500.
| A．not go | B．not going |
| C．don’t go | D．not to go |
. Pointing to the house on ____ roof grew lots of bush, the old man told me that was _____ I would stay.
| A．its; what | B．whose; what | C．whose; where | D．its; where |
You can make a complaint to the local government _____ you are happy with the way things are.
| A．unless | B．if | C．once | D．as |
We finally managed to make the villagers _____ of the value of science.
| A．to convince | B．convincing | C．convince | D．convinced |
— I wonder _____ Mr. Black changed his mind to take part in the movement.
— After he listened to the speech by Mr. King.
| A．when was it that | B．when was that it | C．when that was | D．when it was that |
—He got the first prize in a National Contest of Popular Music.
—Oh. That’s what he _____ for years.
| A．had been expecting | B．has expected | C．expected | D．has been expecting |