They started off at about 5 o’clock in the morning . They should there by now .
A. arrive
B. have been arriving
C. have arrived
D. be arriving
网友回答
A. arrive
B. have been arriving
(答案→)C. have arrived
D. be arriving
解析：考查虚拟语气。句意：他们在上午大约五点钟出发。到现在他们应该到达那儿了。“should+have+done”意思是“本来应该做某事，而实际没做。故选C。