题目:We all know that the normal human daily cycle of activity is of some 7-8 hours’ sleep ______ with some 16-17 hours’ wakefulness.
A. altering
B. differing
C. alternating
D. exchanging
答案:评论后可见此内容
推荐使用我们的公众号搜索题目,题目更全,检索更方便。支持语音、图片、文字等多种搜索方式。