避雷针（网、带）及其接地装臵，应采取自下而（）的施工程序。首先安装（），后安装（），最后安装（）。
参考答案：上；接地装臵；引下线；接闪器
低钾血症的临床表现是
A．肌肉痉挛
B．心律失常
C．厌食、腹胀
D．倦怠、嗜睡
The train ________ arrive at 1:30, but it was an hour late.
A. was about to
B. was likely to
C. was certain to
D. was supposed to
