If I should ……, Imperative Sentence.

　　结构�UIf I+should ……+祈使语气

　　说明�U代替，增加了条件的不确定性。本句型常用在想礼貌地提出要求或建议，或者想圆通地告诉他人该做什么事的场合。用 should 起始句子即可不用 if 而表示条件。这种用法比较正式，常用于诸如公函之中，而不用于日常会话。

　　If you should see him, please give him my regards.
　　如果你见到他，请代我向他致意。

　　Should you see him, please give him my regards.
　　如果你见到他，请代我向他致意。

　　If you should happen to see him, please give him my regards.
　　如果你万一见到他，请代我向他致意。

　　Should you happen to see him, please give him my regards.
　　如果你万一见到他，请代我向他致意。

　　If you should write to her, send her my love.
　　如果你给她写信，请代我向她问候。

　　Should you not wish our agent to call, please let us know.
　　你若不希望我们的代理人去造访，请告之。

　　Should you be interested in our offer, please contact us.
　　你若对我们的报价感兴趣，请与我们联系。