一、基本下课用语

直接告知下课

- Class is over.

- The class is dismissed.

礼貌告别

- Goodbye, boys and girls.

- See you next class.

- See you.

二、课堂过渡用语

开始上课

- Class begins.

- It's time for class.

课程总结

- That's all for today.

- Let's have a rest.

三、其他实用表达

感谢与期待

Thank you for helping me.

I look forward to our next class.

补充说明

The teacher dismissed the class on time.

建议根据具体场景选择合适表达，例如：

上课开始时用 "Class begins" 引导注意；

下课结束时用 "Class is over" 明确告知；

结束课程后用 "See you next class" 建立期待。

以上表达均符合英语课堂的常规交流习惯，可根据实际需要灵活运用。