若0是关于x的一元二次方程（m-1）x²+5x+m²-3m+2=0的一根，则m值为（　　）

嫁接可以分为____和____ 两种方式．接穗与砧木____ 必须紧密结合．

下列少数民族中人口都在400万以上的一组是（   ）

撑起自信的最重要的支柱是（    ）

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.