đề: chuyển các câu sau về thì quá khứ đơn
she buy a book
the teacher punighees the boy
the little girl laughs at the beggar
they know it
he does not tell lies
they do not wait for anybody
who teachers you English
the masons build the house
they invite us their party
he manners disgust me
she sing a lovely song
it is time to starts
he wants to kill the snake
his conduct surprises me
i want you to come with me