These are very useful when speaking English. Many students forget to use them.
For any amount use "some."
I bought groceries at the store.
I bought some groceries at the store.
She has money in her purse.
She has some money in her purse.
There were police at the building.
There were some police at the building.
For large amounts use "a lot of."
He needs help.
He needs a lot of help.
We picked strawberries.
We picked a lot of strawberries.
There are some flies inside the house.
There are a lot of flies inside the house.
Remember that "a lot" can be used when there's not a noun that follows:
A: Did you find any tomatoes?
B: Yeah, a lot.
For small amounts use "not a lot of."
There were people at the party.
There weren't a lot of people at the party.
John has friends.
John doesn't have a lot of friends.
For amounts of zero, use "not" and "any."
She has time.
She doesn't have any time.
There's some bread on the shelf.
There isn't any bread on the shelf
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