Yingying a piece of litter, and put it into the rubbish bag.
| A．picked up | B．threw away |
| C．looked for | D．handed in |
Trees ____ fight air pollution．They are natural air conditioners．
| A．should | B．must | C．need | D．can |
____ it snowed heavily yesterday, nobody in our class missed the lesson．
| A．Though | B．Because | C．Unless | D．Since |
Tomorrow there’s a programmed about our school on TV，then it ____ by millions of people．
| A．will see | B．saw | C．will be seen | D．was seen |
My brother is two meters in height．It’s very difficult to find clothes big enough ____ him．
| A．about | B．at | C．with | D．for |
—Have you ____ joined in a dragon boat race?
—Yes，I have．
| A．never | B．still | C．seldom | D．ever |