【单选题】The farmers,___________houses had been destroyed by the serious flood,were given help by the government.
【单选题】As a result of the serious flood, two-thirds of the buildings in the area .
【判断题】相对于半波振子的天线增益用dBi表示。()
【简答题】天线两臂总长2l=λ的对称振子叫做 (全波/半波)对称天线。A. 全波
【简答题】半波对称振子天线总长2l=A. 波长的一半
【简答题】设以半波振子为接收天线,用来接收波长为λ、极化方向与振子平行的线极化平面波,试求其有效接收面积。
【简答题】基本半波振子的长度是(),而折合半波振子的总长为()。
【简答题】理想导电面上方水平放置的半波振子天线如图(a)所示。
【单选题】第一节 单项填空 从A、B、C、D四个选项中,选出可以填入空白处的最佳选项。 The flood did not start to ______ until two days after the rain had stopped.
【判断题】1.
Two hundred people were rescued by emergency services over the weekend in the
level of the flood. (T/F)