标称对数为30的电缆芯线，中心层外有（）层。
A.1
B.2
C.3
D.4
参考答案：B
— What should I wear for the English speaking composition?
— Dress ____ you like. [ ]
A. which
B. what
C. however
D. whenever
工程师判定风险责任的准则是( )。
A．有经验的承包商在投标阶段能否合理预见B．风险事件的程度C．风险起阅D．承包商抗风险能力
