A lot of and lots of

A lot of / lots of

Watch this video first! https://www.youtube.com/watch?v=r8OsCtXsM6I&feature=youtu.be

It can be used with countable and uncountable nouns. It helps to specify a large amount of something. It is generally used in affirmative sentences but it can be used in negative and interrogative sentences.

Examples:

There are a lot of trees in the park.

Hurry up! we haven't got a lot of time.

I’ve made a lot of friends while I was traveling around Europe.

Use a lot of or lots of for nouns, you cannot count and for plurals. These adverbs of quantity refer to frequency, quantity, and degree.
For countable and uncountable nouns use exact quantities in your answer or use a lot of  / lots of. 

Example: I've got 10 pens. I've got a lot of pens.

Practice!

https://first-english.org/english_learning/english_beginners/a_lot_of_lots_of/01_a_lot_of_exercises_learning.htm