问题
选择题
I know that it will be difficult to pick him out in such a crowd, but if you ________ happen to see him, give him this packet.
A．would
B．might
C．should
D．could
答案
答案：C
C 考察情态动词。If+主语+should+动词原形，是一个真实条件句。常常用于礼貌地请求和建议。故C正确。