请问如何区别many和much的用法?

many修饰复数可数名词,表许多； much修饰不可数名词,表量或程度.
He has many friends,but few true ones.
There hasn't been much good weather recently.
（2）many a:
many a和many同义,但语气比较强,并且要与单数名词及单数形动词连用.
Many a prisoner has been set free.(=Many prisoners have been set free.)
〔3〕as many和so many均等于the same number of.前有as,like时,只用so many.
These are not all the books I have.These are as many more upstairs.
They worked like so many ants.
（4）as much等于the same amount of,表同量和同一事情.
He bought two pounds of sugar and as much tea.〔同量）
I was not in the least surprised,for I had fully expected as much.〔同一事情）
（5）many和much之后不接名词时,作为代名词；另外much也可用副词.
Many of them were very tired.
I don't eat much for lunch.〔代名词）
He is much taller than I.（副词）