"To attend class on time" 是指按时上课的意思。这个说法来源于英语中 "on time" 这个短语，意思是 "按时，准时"。

例句：

It's important to attend class on time. (重要的是要按时上课。)

Please make sure to arrive at class on time. (请确保按时到达上课地点。)

I always try to attend class on time, but sometimes traffic gets in the way. (我总是尽量按时上课，但有时交通会阻碍我。)