选择题：15.Mary ________ show us her new dictionary . ( )(

题目内容：

15.Mary ________ show us her new dictionary . ( )(本题1.5分)
A. has asked to
B. was asked to
C. is asked
D. asks to

参考答案：

图素的简单含义是（ A ）"

数组对象的长度在___创建之后,就不会改变。数组元素的下标总是从___开始。(本题4.0分)

沥青路面的强度与稳定性除与面层有关外，在很大程度上取决于 A.地下水位的高低B.材料的水稳性C.土基和基层的性能D.荷载作用的性质

19. 如下图所示正弦稳态电路,各电压表读数为有效值,其中V1=30V,V3=50V,则V2为( )(本题2.0分)A. 30VB. 40VC. 50VD. 2

This fire extinguisher is to be used only in case of ______________.A. urgency