表示时间的介词at,in,on的用法最容易混淆,中考中也常将它们作为重要的考点来进行考查。现将它们的主要用法归纳如下:一、何时用at?1.用于表示在时间的某一点或某一时刻。例如:We start classes at eight o’clock in the morning.我们上午八点开始上课。What were you doing a The use of the prepositions at, in, and on the time is most likely to be confused, and they are often examined as important test points in the middle of the exam. Their main usages are now summarized as follows: 1. When to use at?1. Used to indicate a point or time at a certain time. For example: We start classes at eight o’clock in the morning. We start classes at eight in the morning. What were you doing a