Teacher：Yesterday, we learned some important geographical facts. I hope you all still remember them. I’m going to test you now by asking a few        questions. First, what’s the highest mountain in the world?

Boy 1：Qomolangma! It’s higher than any other mountain in the world.

Teacher：That’s right. And who can tell me what the Sahara is?

Girl 1：The Sahara is the biggest desert in the world.

Teacher：Very good. And which is the deepest salt lake in the world?

Girl 2：The Caspian Sea is the deepest of all the salt lakes.

Teacher：You’re all so smart! Now, for the last question, which is the longest river in the world?

Boy 2：I know! The Nile is the longest river in the world.

Boy 1：And the Amazon is the second longest river in the world.

Teacher：It seems that you know the answers to all my questions. Good job!