用括号内所给单词的适当形式填空

1. How much________ (be) the T-shirts?

2. She needs 120________ (dollar) for it.

3. Come down to see the Zigzag's________ (clothes) Store. 

4. People like________ (it) cheap.

5. Can you_________ (buy) the shirt?

在软件生存期的维护扩充阶段，软件所要求的质量特性是

A．易使用性和可移植性

B．安全性和重用性

C．可扩充性和可靠性

D．可维护性和可扩充性