除了北京奥运会，中国国奥队参加了几届奥运会的男足比赛（）
A.0
B.1
C.2
D.3
参考答案：A
A．仅把R1的触头向右滑动时，电流表读数减小，油滴向下运动
B．仅把R1的触头向右滑动时，电流表读数减小，油滴向上运动
C．仅把两极板A、B间距离增大，油滴向下运动，电流表读数不变
D．仅把两极板A、B间相对面积减小，油滴向下运动，电流表读数不变
用所给单词的适当形式填空。
1. Giraffes like eating the (leaf) of trees.
2. Dogs are very (friend) to us. They can help us a lot.
3. We want to see the koalas (one).
4. How many (monkey) can you see?
5. What is it? You can have three (guess).
