单选题 They left at nine, so they ______ by now.
A. may arrive B. must arrive
C. should have arrived D. ought to arrive

【正确答案】 C
【答案解析】[解析] should have arrived by now现在应该已经到达了。“should have+过去分词”用于判断，表示说话时某人应该已经做了某事，也可表示“本来应该已经做了某事(但实际上并未做)”，含有责备之意。