Let's have a look at some common mistakes of English learners. How many could you correct without looking at the answers?

Incorrect: My sister is photographer.
Correct: My sister is a photographer.

Incorrect: It is more cold today.
Correct: It is colder today.

Incorrect: I have told you all what I know.
Correct: I have told you all (that) I know.

Incorrect: Which is the biggest city of the world?
Correct: Which is the biggest city in the world?

Incorrect: I have done a mistake.
Correct: I have made a mistake.

Incorrect: I have been here since three days.
Correct: I have been here for three days.

Incorrect: We waited one and a half hour.
Correct: We waited one and a half hours.

Incorrect: According to me, it’s a bad film.
Correct: In my opinion, it’s a bad film.

Incorrect: It’s getting winter.
Correct: It’s getting to be winter.

Incorrect: Except Angie, everybody was there.
Correct: Except for Angie, everybody was there.