单项选择题
He must have had an accident，or he（）then．
A.would have been here B.should be here C.had to be here D.would be here
单项选择题 Has any person（）on board during the voyage otherwise than as a result of accident?
单项选择题 Fracture damage to the end links of the anchor cable，or to the jews’ harp may be eliminated by（）.
单项选择题 Dunnage may be used to protect a cargo from loss or damage by（）.
