【关于含蓄条件句的问题1,请问butfor是不是和without可以互换的,如Butforyourhelp,wewouldbeworkingnow.=Withoutyourhelp,wewouldbeworkingnow.Withoutyourinstruction,Iwouldnothavemadesuchgreatprogress.=Bu】

　　关于含蓄条件句的问题

　　1,请问butfor是不是和without可以互换的,如Butforyourhelp,wewouldbeworkingnow.=Withoutyourhelp,wewouldbeworkingnow.

　　Withoutyourinstruction,Iwouldnothavemadesuchgreatprogress.=Butforyourinstruction,Iwouldnothavemadesuchgreatprogress.对吗?

　　2,在含蓄条件句中,主句的虚拟语气的结构是和If引导的条件句的主句的虚拟语气的结构一样的吗?还是只可以用“would（not）+动词原形”以及“would（not）+have+done”呢?