按金属材料破裂的现象不同，把压力容器的破裂分为韧性破裂、（）、疲劳破裂、（）和蠕变破裂五种形式。
参考答案：脆性破裂 ；腐蚀破裂
— Hello, may I speak to Liming, please?
— I'm sorry, you _____ have the wrong number. There's no one in our office with that name. [ ]
A. may
B. would
C. should
D. must
一定时期内每期期初等额收付的系列款项是( )。
A．预付年金 B．永续年金 C．递延年金 D．普通年金
