—Do you know when Britain ______war on Germany during the Second World War?
—In 1993，I suppose.
| A．announced | B．declared | C．fought | D．attended |
—Why don’t you wear your jogging shorts, mum?
—Well, my legs are too skinny, if you ______ know.
| A．must | B．can | C．may | D．need |
Tourists are now coming to Ping’an village in large numbers, ___________ they would never have stopped, had it not been Mo Yan’s hometown.
| A．when | B．where | C．that | D．which |
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 |