为什么不是I don't believe 而是 I believe not?-- Do you think it's going to rain over the weekend?-- I believe not习惯用法么?

为什么不是I don't believe 而是 I believe not?-- Do you think it's going to rain over the weekend?-- I believe not习惯用法么?
为什么不是I don't believe 而是 I believe not?
-- Do you think it's going to rain over the weekend?
-- I believe not
习惯用法么?

为什么不是I don't believe 而是 I believe not?-- Do you think it's going to rain over the weekend?-- I believe not习惯用法么?
I don't believe 更多的带有自己的主观意愿,具有主动性.
I believe not 则是强调客观事实的发生性小,客观性强.
这里应该是习惯用法.
这里I believe not 是简略回答,完整的应该是I believe it will not rain over the weekend.
特殊注意：回答问句时通常用I believe so/not的形式.