关于英语中的虚拟语气,求解答!急!

关于英语中的虚拟语气,求解答!急!
Q1: 句一：It looks as if it is going to rain.
句二：The apple tastes as if it is sour.
这两句是虚拟语气吗?如果不是,请问为什么不用虚拟语气；如果是,请问为什么be不是用were的形式?
Q2：
选择题：1、____fired,your healthy care and other benefits will not be immediately cut off.
A.Would you be B.Should you be C.Could you be D.Might you be
这句话该怎么翻译,答案该选什么,为什么?
2、She wishes she____that humiliating thing.
A.doesn't do B.didn't do C.haven't done D.hadn't done
答案是选D,为什么不可以是B呢?不是说在 I wish--这种形式中的虚拟语气中,动词是采用did或had done吗?求解~~~~~
3、It is vital that he ____ immediately.
A.should go B.must go C.goes D.went
请问答案是什么,请求语法解释
4、Were it not for the snowy weather,we____there by now.
A.would get B.would have got C.have got D.may get
答案是选B,可是我觉得应该A才对啊,求解!

Q1非虚拟
Q2
1.B如果你被解雇了,你的健康保险和其他的受益项将不会被立即撤销
2.D混合虚拟,从句是针对过去虚拟的
3.It is vital that+should+动原
4.we____there by now.注意by now.意思是到现在为止我们已经到哪儿了,即过去就到了,故用
would have got