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
网友回答
A. would
B. might
(答案→)C. should
D. could
解析：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。