if…not与unless在这里都能用吗?I'll be surprised if he doesn't have an accident.I'll be surprised unless he have an accident.这两句对吗?为什么?

if…not与unless在这里都能用吗?I'll be surprised if he doesn't have an accident.I'll be surprised unless he have an accident.这两句对吗?为什么? not if与unless 区别 这里的,not unless unless与if…not表示否定条件时有何区别? unless与if…not表示否定条件时有何区别 【英语语法】Unless 和 If not 能互换吗? if...not和unless怎么转换 unless 和 if not怎么互换? if not 和unless有什么区别 if whether都能用吗 unless until if. notunless until if. not 区别用法 unless 与if not帮我分析一下例句：I'll be surprised if he doesn't have an accident.（这句可以用unless来换么?为什么）I'll be back tomorrow unless there's a plane strike.(为句可以用if not来换么?为什么）unless=if not, shall i tell your best friends what happened to you yesterday?()they ask you为什么选not unless 为什么not if not except not though都不行 中国教育集团中教联盟老师unless和if not能互换吗? something 能用在否定句吗?我在书上看到一句话：I can watch TV for hours if my parents do not make me do something else.这里是个否定句,something是否应该换成anything呢? if与or not可以连用吗?先看一个题,答案上选A,I wonder( ) I will catch the last bus or not.A.whether B.if可是我查了许多语法书,有些说whether/if都可以与or not连接使用（whether/if…or not）,只是if不能与or not I won't go there unless I'm invited.这里的unless I'm invited可以像if一样移到开头吗? 用unless=if not 造句 2个