(turn) on your computer and connect to the internet. (open) your e-mail program. (click) on the letter. (type) your e-mail in the big and empty box. 怎么判断是不是祈使句??还是动词做主语?句首的动词要不要加ing?
祈使句中,是没有主语的,动词直接位于举手,表示一种命令或请求; 动词如果位于句首,必须用ing的形式,并且该句的谓语动词必须是单数第三人称的形式。 eg. 1、Finish your homework on time!(表示命令) (Please)Help me! I can not move it.(表示请求) 2、Learning more knowledge is of great importance for us.