Question

There should be many differences betweenthese two

为什么会是many difference?many 不是用在否定句和疑问句中的吗？

Answer 1

many，形容词，许多的。
可以用在肯定句，否定句和疑问句中，用来修饰可数名词复数。
There should be many differences between these two.他们两个之间应该有很多不同点。
differences，名词，不同点。
例：
There are many vegetables on the plate.盘中有许多蔬菜。
There aren't many birds in the tree.树上的鸟不多。
Are there many onions in the fridge?冰箱里有很多洋葱吗？

Answer 2

any才是用在否定句和疑问句中的。