There is a lot of water in the glass.改为否定句：There is not much water in the glass.

There is a lot of water in the glass.改为否定句：There is not much water in the glass.
There is a lot of water in the glass.改为否定句：There is not much water in the glass.

There is a lot of water in the glass.改为否定句：There is not much water in the glass.
也可以
应该是there is not a lot of water in the glass.或
there is a little water in the glass

there is not any water in the glass.

There is little water in the glass.

对的，你也可以直接在系动词is上否定,变成isn't a lot of

There is not much water in the glass.
There is little water in the glass.
there is not a lot of water in the glass.都是正确的
ps：其他几位回答有语病