Select the mistake in each sentence

5: Select the mistake in each sentence.

18. This is Nam. He is an new pupil in our class. He comes from Ha Noi city

A. This          B. comes           C. an            D. our

19. Try to guess new words when you see it.

A. guess        B. it           C. words             D. you

20. Who often do you study science? - I study it twice a week

A. study    B. twice         C. you          D. Who