if you want a share of the pay ,you'll have to do your fair

if you want a share of the pay ,you'll have to do your fair share of the work.
说下虚拟语气,时态有哪些变化情况,最好能举例句说明,还有中间为啥要用逗号隔开.谢谢回答!

这句话也不是虚拟语气呀,就是一个真实条件状语从句
翻译：如果你想得到一份报酬,你必须要做好你的分内工作.
解析：if引导的条件状语从句可以分为两类：真实条件句（Sentences of Real Condition）和虚拟条件句.凡是假设的情况发生性可能很大,就是真实条件句；当假设是不大可能实现时,就是虚拟条件句.如：
If I have time,I will help you with this work.
如果我有时间,我会帮助你做的.
If time permits,we'll go fishing together.
如果有时间的话,我们就一起去钓鱼.
If I were you ,I would have attended the meeting.
我要是你的话,就去参加会议了.
If he had come here yesterday,he would have seen his old friend.
假如他昨天来这儿的话,就会看见他的老朋友.
下面我们一起看看if在条件状语从句中的虚拟语气.
1.表示与现在事实相反的情况.其句子结构为：从句：if + 主语+ 动词的过去式(be 用were) + ……主句：主语+ would (should,could ,might) + 动词原形+ ……
If I were you,I would read it again.
如果我是你的话,我再读一遍.（事实上我不是你）
If he hurried,he could catch the first bus.
他要是快点能够赶上头班公共汽车.（可他不急）
If she knew English,she would not ask me for help.
如果她懂英文,她就不必要我帮了.
2.表示与过去事实相反的虚拟条件句.其句子结构为：从句：If + 主语+ had +过去完成式动词+ ……主句：主语+ would (should,could,might) + have +过去完成式动词+……
If you had taken my advice,you would not have made such a mistake.
如果你听了我的劝告,就不会犯这样的错误.（事实上你没有听我的劝告）
If it had rained yesterday,we would have stayed at home.
如果昨天下雨的话,我们就会留在家里.
If I hadn’t been ill yesterday,I might have come to school.
昨天要是不生病,我是可能来上学的.（事实上我生病了）
If you had studied harder last term,you could have passed the exam.
如果你在上个学期用功一些,你就会在考试中过关了.
3.表示与将来事实相反的虚拟条件句 (对将来的事实实现的可能性不大).其句子结构为：从句：If + 主语+ should (或were) + 动词原形+……主句：主语+ would (could,should,might) + 动词原形+……
If it should rain tomorrow,I would stay at home.
如果明天下雨的话,我将待在家里.（根据天气情况,明天不可能下雨）
If he came tomorrow,I would do it with him.
如果明天他来的话,我将和他一起做此事.（事实上他来的可能性很小）
If he were here,I would give him the books.
如果他在这儿,我可能会把书给他.
有不明白的请继续追问,
再问： If he came tomorrow, I would do it with him. 为什么用came而不是原型come？ If I were you, I would read it again. If he were here, I would give him the books. 这两句是不是要根据语义来判断是与现在事实相反、还是与将来事实相反？
再答： 是的，你写的这几个句子都是虚拟语气，第一句是与将来事实相反的假设，第二句和第三句是与现在事实相反
再问： If he come tomorrow, I would do it with him.这样对吗？
再答： 如果表示虚拟，与将来事实相反的假设，应该写成 If he came tomorrow, I would do it with him. 如果表示真实条件句，则用主将从现 If he comes tomorrow, I will do it with him.