学进去

阅读短文判断正误，用T/F表示。
On Sunday morning, David and Jim are in the hospital. They want to see their English teacher Miss Yang. There are a lot of public signs there. They mean different things. The boys know a lot about them. They see a sign on the wall. It means "Be quiet". So they don't make any noise there. Suddenly, David sees a woman littering. He comes up to her and says, "Excuse me, you can't litter here. Look at that sign, it says,' No littering'." The woman says sorry.
(      ) 1.Miss Yang is a doctor in the hospital.
(      ) 2.There are some public signs in the hospital.
(      ) 3.The boys don't know a lot about the signs.
(      ) 4.The sign on the wall means "Keep quiet".
(      ) 5.The woman doesn't see the sign.