选择题：Since they aren’t answering my telephone, they ___

题目内容：

Since they aren’t answering my telephone, they ________.
A、 should have left
B、 need have left
C、 would have left
D、 must have left

参考答案：

在站场信号平面布置图上，站场股道的编号，正线编为( )数字。A、阿拉伯数字B、罗马数字C、单数

在站场信号平面布置图上，站场股道的编号，正线编为( )数字。A、阿拉伯数字B、罗马数字C、单数D、双数

How much has the company ________________ this year?选择一项：A. brought down B. brou

如图所示圆轴.已知F=8kN,M=3kN.m,［σ］=100MPa,若用第三强度理论求轴的最小直径，则D≥（）mm。 A、 79.8B、 66.7C、 77.

_________ time and labor, cartoonists generally draw the hands of their characte