Question

quite a lot与quite a lot of

Answer 1

意思都是许多，非常多，只是前者后面不加名词，后者of后面要加名词：
In fact, they share quite a lot in common. 事实上，他们确实有很多共同之处。
I know quite a lot about you. 我知道很多关于你的事儿。
They attract quite a lot of attention. 它们引起了非常多的关注。
In the distance, quite a lot of people are working. 远处相当多的人正在劳作。

Answer 2

quite a lot 作状语

quite a lot of 后面加名词，组成名词词组

Answer 3

quite a lot加动词/形容词/副词、quite a lot of 加名词