阅读小天地。

      There are fifty students in Bob's class. There are twenty-six girls and twenty-four boys. It's Sunday today.

They're having fun in a park. Some students are singing. Some are jumping. Some are playing badminton. Bob

is flying a kite. They are all laughing. They're very happy!

根据短文内容判断，下列句子的正(√)误(×)。

( ) 1. There are twenty-six boys in Bob's class.

( ) 2. It's Sunday today.

( ) 3. They are in a zoo.

( ) 4. Bob is singing.

( ) 5. They're not happy.

在供应商选择的QCDS原则中最重要的是（）

A.质量，即Quality

B.成本，即Cost

C.交货期，即Delivery

D.售后服务，即Service