I like this dress. I like that dress.（两句并一句）

i like this and that dresses.
或者
i like these two dresses.

I like not only this dress but also that one!

I like both dresses.

I like both dresses.
最简单

I like both this and that dress.

I like the dresses

哪有二楼那样翻译的。
最好的说法是：I like both this and that dress.

i like both of the dresses. 不用加two，both就包括了这个意思。另外dress的复数是不是dresses有点不确定，一般情况下dress不用复数

I like both this dress and that one.

I like dress this dress.

I like this dress as well as that one.