The dancers, all of _______ masks came off suddenly, gave us a great surprise.
| A．their | B．whose | C．which | D．whom |
Medicine and food ________ to the flood areas soon.
| A．send | B．was sent |
| C．will send | D．will be sent |
When _______ comes to advertisements, we must all use our intelligence.
| A．that | B．it | C．there | D．this |
________ he found the idea interesting, it was too difficult to be of practical use.
| A．While | B．Once | C．If | D．Until |
As they were walking around, they noticed a man _______ against a tree.
| A．sit | B．to sit | C．sitting | D．sat |
Do some warming up exercise before sports. Or you _______ hurt yourself.
| A．must | B．need | C．should | D．may |