Should you come to Brunei, you would have to take off your shoes before going into someone’s house.
     你要是到文莱的话，进入房间前要脱掉鞋子。

     该句是一个虚拟条件句，表示与将来的事实可能相反的假设和结果，同时条件句中省略了连词if，要将should提前倒装。在虚拟语气中，表示与将来事实可能相反的假设，条件状语从句的谓语一般用过去式/should+动词原型/were to+动词原型，主句谓语为would/should/could/might+动词原型，如果状语从句中含有助动词，那么连词if可以省略, 但从句部分要用倒装语序，将should/ were 移至句首。如：
Were it Sunday tomorrow, we should go to the Great Wall.
要是明天是星期日，我们就能去长城了。
Should he win the game this time, he would win 10 gold medals altogether.
假如他赢得这次比赛，他将总计获得十块金牌。

重点语法：虚拟语气在条件句中的使用

1. 与现在事实相反的假设。
句型 ：条件从句主句
一般过去时should( would) +动词原形
例如：If they were here, they would help you.
      假如他们在这儿的话，他们会帮助你的。
2. 与过去事实相反的假设。
句型：条件从句主句
过去完成时  should(would) have+ 过去分词
例如：If she had worked harder, she would have succeeded.
      假如她再努力一点的话，她就成功了。
3. 表示对将来不大可能实现的情况的假设
句型：条件从句 主句
一般过去时 should+ 动词原形
were+ 不定式 would + 动词原形
should+ 动词原形
例如：If you succeeded, everything would be all right.
    If you should succeed, everything would be all right.
    If you were to succeed, everything would be all right.
    如果你成功了，一切就会好了。