用括号内所给动词的适当形式填空。
1.We ____(watch) the boys____ (play) basketball on the playground when something strange happened.
2.I don't know what ____(happen)to him just now.
3.Computers are useful to us. But some students only use them____ (play) games.
4.–--Would you mind____(take) photos with me?

5.--- Of course not. When I miss you, I can have a look.

6.You may go to play football as soon as your homework ____ (finish).
7.Middle school students____(tell) not to smoke.   

328____1234         9258____8364        7654____7564

已知a为$\sqrt{170}$的整数部分，b﹣1是400的算术平方根，求$\sqrt{a+b}$的值．

音箱上的喇叭是（　　）

利用人工合成的昆虫性外激素可以诱捕相应的农业害虫．（判断对错）