1、many 修饰可数名词

I have many books.我有许多书。

many作主语时谓语动词用复数。

Many books are new.许多书是新的。

2、much 修饰不可数名词

There is much water in the glass.杯子里有许多水。

much作主语时谓语动词用单数。

Much time has been wasted．有许多时间给浪费掉了。

3、a lot of=lots  of 修饰可数名词和不可数名词

There are a lot of（many） people in my family.我家有许多人。

There is a lot of（much） time to us.对于我们来说还有许多时间。

a lot of引导名词做主语时，谓语动词的数不是复数，而是根据of所引导的名词的数来决定。

A lot of（Lots of） people have been here。许多人都在这。

A lot of（Lots of）money was lost.许多钱都丢了