一个虚拟语气倒装的语法问题

Question

Should you experience any difficult , do not hesitate to contact
one of my staff members.为什么第一个用的是Should ？

Answer 1

Should you experience any difficult, do not hesitate to contact one of my staff members.
一、句子使用语气的解释：
这是个“虚拟条件句 + 祈使句”的复合句
1. 条件虚拟语气在这里是一种客套语，即不强求对方非得接受 。
2. 祈使句也是一种客气，表示请求
二、关于条件虚拟的倒装：
条件虚拟句常可以用倒装语序表示。倒装时只要省去 if 再把助动词或情态动词提前放在主语前即可，如本句：
提前 should：Should you experience any difficult = If you should experience any difficult, 假如你们觉得有什么难题的话，
再如：
* 提前 were：Were you to be here tomorrow, ... = if you were to be here tomorrow, ... 假如你明天会在这里的话，...
* 提前 did：Did he come now，... = If he came now,... 如果他现在就来的话，...
* 提前 had：Had the students finished their homework on time, ... = If the students had finished their homework on time, ...如果学生原来就按时完成了作业的话，...

Answer 2

因为这里用的类似倒装的结构。
If的虚拟从句中should可以提到句首并省略if。
只有should、were to、had有这样的用法。

Should you experience any difficult = If you should experience any difficult 表示对将来的虚拟。

Answer 3

在if引导的虚拟语气条件从句中，若有should.
were
.
had
.
那么在书面语气中就可以省略if，将这几个词提到句首，构成倒装。

Answer 4

英语虚拟语气中，当If条件句中存在should/had/were时，可以省略if，而把这几个词提于句首，再如：
If I were you,I will accept the teacher's advice.
=Were I you,I will accept the teacher's advice.
If I had had much money, I would have bought the beautiful car.
=Had I had much money,I would have bought the beautiful car.

Answer 5

If 引导的虚拟条件状语从句的倒装使用方法

含有虚拟语气的条件状语从句中，如有had, should, were 这三个词的话，在正式或书面语中可以将if省略，再将句子的主语和谓语动词实行全部倒装或部分倒装。例如：

Were I you, I would go.如果我是你，我就会去。