【简答题】天线的基本功能是 。发射时,把传输线中的高频电流转换为 ;接收时,把 转化为传输线中的高频电流。
【判断题】大型水工建筑物施工结束,变形监测就相应停止( )
【单选题】A copper producer is worried about the copper prices going down. The risk of downward movement in prices can be hedged by taking one of the following potions
A.
Buying call options on copper
C.
Selling copper futures
D.
Selling copper call options
【简答题】倒垂线常用作变形监测的基准线,可用于水工建筑物的( ) A应变监测 B水平位移监测 C垂直位移监测 D裂缝监测 E挠度监测
【简答题】天线基本功能是 。发射时,把传输线中的高频电流转换为 ;接收时,把 转换为传输线中的高频电流。
【简答题】对水工建筑物进行监测与维护,必须本着 [填空(1)] 的原则。
【简答题】A.The customers. B.Increased sales. C.The producer. D.Reduced prices.
【判断题】The producer prices index (PPI) is constructed to measure the change in price of total production