And the first question I think that you have on the quiz here is the following: what keyboard instrument is playing here?

这里有个小测验,第一个问题是,这段音乐是用什么键盘乐器演奏的

耶鲁公开课 - 聆听音乐课程节选

And most of these commands you don't actually need but this little caret symbol means control, so every keyboard these days has a control key so you hold that and hit X for instance to exit the program.

这里大多数命令你们都用不着,这个小插入符意味着控制，每个键盘都有一个控制键,譬如，当你敲入X时，就退出这个程序。

哈佛公开课 - 计算机科学课程节选