含消化酶种类最多的消化液是（）
A.唾液
B.胃液
C.胆汁
D.胰液
E.小肠液
参考答案：D
Peter says that the Whites are on holiday, but no one knows_____ .[ ]
A. where they have been
B. where are they
C. where are they from
D. where they have gone
( )是指材料在外力作用下产生塑性变形而不破坏的能力。
A．刚度
B．弹性
C．塑性
D．韧性
