一个直角三角形三边的长成等比数列，则（ ）

    Today is Sunday. It is a sunny day. Mike and Paul are going to have a picnic in the park. There are many green trees. Near the gate，there is a lake. Some ducks are swimming on the lake.

    Mike and Paul are going to have lunch at half past eleven. Then they are going to read some books under a big tree.