i will shop this sunday.对吗

没错。更好的表达为：I am shopping this Sunday.
或I will go shopping this Sunday.

对的

I will go shopping this Sunday好一点

I will go shopping this Sunday.

这样应该更好

will shop 会买
will go shopping 会去买

我觉得will shop是肯定句，就是你一定会买东西的
但是go shopping就不一定了，是逛商场的意思，不一定会买。

对