Question

Come in and have some water.把这个祈使句改成否定句。

Come in and have some water.把这个祈使句改成否定句。两个疑问，and要不要改成or，some要不要改成any？

Answer 1

字面上可改为：Don't come in or have any water.相当于：Don't come in and don't have any water.
但实际上是没有这种情况的。这本是口语中的一句邀请话，意为：请进来喝杯茶。是先进来然后喝茶，后者是承前者发生的，既然不进来，也就无所谓喝茶了。即，没了前者也就没有后者。
我个人认为，既然Come in and have some water.与Will you come in and have some water?相当， 只不过后者比前者更委婉些，那么前者的否定就可用 Won't you come in and have some water?来构成否定。
以上为一家之言，仅供参考。

Answer 2

Don't come in and have any water.
这是语法练习，一般还是按部就班some 改any。一般口语中不会这么强制作否定转换。后面改了any对应don;'t更明确。

希望对你有所帮助。

Answer 3

I don't want to come in or have some water.