喷射混凝土和喷浆支护可以起到（）作用。
A．结构
B．充填
C．悬吊
D．隔绝
E．柔性支护
参考答案：A, B, D, E
内部收益率的定义是什么？两种定义法有什么区别和联系？各自适用于什么场合？
35. —Hey, Kelin. Happy new year! ______?
—Ok, I guess. My grandma kept cooking and cooking, so I just kept eating.
A．How was your break
B．How is your grandma
C．Where did you go for holiday
D．What did you do in your holiday
