would rather+(not )have done,对过去的虚拟，表示过去某种选择不正确
i took Salluy to the cinema last nighrt,but i would rather have been there alone.
would rather sb did sth,宁愿让别人做某事。从句谓语用一般过去式。表示与现在或将来相反。
i would rather you came next week,虽然next week 是将来时，但谓语用came
would rather sb had done sth,宁愿某人过去做了某事，实际没做。表示与过去事实相反，用过去完成时。
i would rather you had not made a mistake,我倒是希望你没出错。
it is （hight） time that +定从，从句谓语多用过去式，也可用should+V，should不能省
it is hight time that we should have a rest.
as if/though
the injured man acted as if nothing had happened,哪个受伤的男人表现的好像什么也没发生。（与过去相反）
