Lesson 91 How long've you been here?

Narrator: It's midnight.Two policemen are outside the library.

1st Policeman: Look at that!

2nd Policeman: What?

1st Policeman: A light's on in the library.

2nd Policeman: That's funny. The library's shut.

1st Policeman: Let's climb in and see.

2nd Policeman: Look! There's a man in the reading-room.

1st Policeman: What are you doing here?

Professor: I'm reading.

2nd Policeman: But it's midnight!

1st Policeman: How long've you been here?

Professor: I've been here since this morning.

2nd Policeman: He's been here for fifteen hours!