倘若您不小心将课程退选，只要课程时间尚未结束，便可再次加选此课程。
再次加选后，您先前的修课纪录（例如：作业测验的缴交纪录）仍然存在，并不会重新来过。
If you drop from the course, you can enroll again while the course is still open.
Your learning record will still be there, you don't need to start over again.