Vessels must （） pilot at waiting anchorage． ["wait","wait for","be waited","be waited for"]
工程中GSM系统同频干扰C/I要求大于（）dB，邻频干扰要大于（）dB。
简述CDQ循环气体的流程。
The main bearing shells are made of steel with a lining of bearing metal which may be white metal, copper-lead or aluminum-tin alloy What is the meaning of “which” in the sentence above?（） ["main bearing shells","main bearing","steel","bearing metal"]
非火山型张裂边缘的特征如何？
简述大陆张裂的单剪模式
