Some verbs are directly followed by direct objects without prepositions. Examples are: discuss, enter, marry, lack, resemble and approach.

Incorrect: My father loves with me.

Correct: My father loves me.

Incorrect: We reached at the airport.

Correct: We reached the airport.

Incorrect: He ordered for my dismissal.

Correct: He ordered my dismissal.

Incorrect: John married with his cousin.

Correct: John married his cousin.

Incorrect: Jane entered into the room.

Correct: Jane entered the room.

Prepositions are not used in expressions of time beginning next, last, this, one, each, every, some, any and all.

Incorrect: See you on next Monday.

Correct: See you next Monday.

Incorrect: I will be rich on someday.

Correct: I will be rich someday.

Incorrect: We met on one Friday in February.

Correct: We met one Friday in February.

Prepositions are not used directly before the conjunction that.

Incorrect: I knew about that she had decided to quit.

Correct: I knew that she had decided to quit. OR I knew about her decision to quit.

Incorrect: I had no idea of that she had problems.

Correct: I had no idea that she had problems. OR I had no idea of her problems.

Prepositions are not normally used before infinitives in English.

Incorrect: I am thinking of to write a novel.

Correct: I am thinking of writing a novel.

Incorrect: I don’t like the idea of to get old.

Correct: I don’t like the idea of getting old.

Incorrect: She is very good at to cook.

Correct: She is very good at cooking.