Who can answer this question? 谁能回答这个问题？
Who wants to do it on the blackboard? 谁愿意到黑板上来做？
Raise your hands, please. / Hands up, please. 请举手。
Just hands. No voices. 不要说，请举手。
Hands down. 把手放下。
Come up to the front, please. 请到前面来。
Go back to your seat, please. 请回座位。
Can you guess it? 能猜猜吗？
Take your time. 慢慢来。
Use your head. 动动脑筋。
Take it easy. / Don't be nervous. 别紧张.
Come on. You can do it. 来吧！你能做到的。
Come on, you're almost there. 来吧！你快（做/答）对了。
I'll give you a clue / hint. 我给你一些提示。
Any one can help him / her? 谁来帮他/她一下？
Are you through? / Have you finished? 做完了吗？
Any different opinion? 有不同意见吗？
Good job. / Good try. / Well done! 完成得不错。
Terrific! / Wonderful! / Excellent! 很棒！
Good idea! That makes sense. 好主意，有道理。
Please give him / her a big hand. 请给他/她一些掌声。
结尾
That's all for today. / We stop here for today. / Let's call it a day. 今天就到这儿。
Please pass the exercise books to the front. 请将练习本递到前面来。
Here are your exercise books. Please hand them out. 这是练习本，请发下去。
Here's your homework for today. 这是今天的家庭作业。
Hand in your homework tomorrow. 家庭作业明天交。
Come and see me after class. 课后找我。