不大可能的英语

that's impossible.

That may be impossible.

英语：unlikelyYou will certainly hear it argued, but it seems unlikely in my view. 你必然会看到这种解释，但是我却有不同观点。

That's very unlikely.这个是最典型的英语习惯表达

That's impossble 不确定 Because my English is very poor

不大不小英语怎么说?--不能固定思考，这里的“不大不小”其实就是“普通，一般”的意思建议用common或者ordinary，就可以了