Each test comes in advance with a prep sheet telling you how to get ready for that particular test.

每次测试前都会给你们考点,那里面会告诉你如何备考

耶鲁公开课 - 聆听音乐课程节选

In this case, I probably want to make sure I use absolute value of x before I carry it on. Yes ma'am.

在这个例子中，我可能想确定,在进行测试前我用的是x的绝对值,什么问题？

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