喷射砼支护作用原理有哪些？（）
A、支撑作用
B、充填作用
C、隔绝作用
D、柔性支护作用
参考答案：A, B, C, D
两栖动物不能完全适应陆地生活的主要原因是[ ]
A．肺不发达
B．体温不恒定
C．生殖发育离不开水
D．心脏结构简单
Mr Lin gave the textbooks to all the students _____ the ones who had already taken them. [ ]
A. except
B. including
C. among
D. with
