问题
选择题
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
答案
答案：C
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。