祈使句一般是省略主语You,改成陈述句,要将主语还原
主语+can/can't+动词原形
Eg：Don't open the door.
You can't open the door.那Open the door，please. 呢？改成You can open the door.吗？好像不太合适。我觉得只能改成Can you open the door, please? 祈使句和Can的转换，应该没有特定的吧。你参考一下面的转换英语祈使句句型转换　　　　祈使句与陈述句的改写　　1．祈使句=You must …（陈述句）　　Come here .过来。　　=You must come here .　　你必须过来。　　Don''t do that again.　　你一定不可以再那样做了。　　2．Please +祈使句=Will you (please) ～?（陈述句）　　Please help me .请帮帮我。　　=Will you (please) help me?　　你愿意帮我的忙吗？　　Come here on time ,please .请准时到这儿。　　=Will you (please) come here on time ?　　请你准时到好吗？