Incorrect omission of prepositions

Pay for a thing, not pay a thing.

Don’t say: How much did you pay the book?

ü  Say: How much did you pay for the book?

Note: A person can pay another person. He/she can also pay a bill, an account, or a subscription. He/she pays for a thing that he/she buys.

Incorrect omission of prepositions

Ask for a thing, not ask a thing.

Don’t say: She came and asked my book.

ü  Say: She came and asked for my book.