21的因数有（ ），27的因数有（ ），（ ）既是21的因数，又是27的因数。
1、3、7、21；1、3、9、27；1、3
读短文，选答案。
There are four seasons in a year. Spring begins first. Summer is the second. Then it's fall. Winter is the last season in a year. In China, the weather is not the same in winter. In Beijing, it's very cold. It often snows. People
can play with snow and they must put on the coat. But in Hainan it's not cold. It's very warm. People there can
go swimming in the sea.
1. What's the weather like in winter in Hainan?[ ]
A. It's very cold.
B. It's not cold.
2. How many seasons are there in a year?[ ]
A. Four.
B. Five.
3. What's the third season in a year?[ ]
A. Spring.
B. Fall.
4. Can people see the snow in winter in Beijing?[ ]
A. Yes, they can.
B. No, they can't.
5. Can people make a snowman in winter in Hainan?[ ]
用○、△、□画出：从六个图形中随意拿一个，不可能是△．______．
