用that 或if或 whether造一个宾语从句

用that 或if或 whether造一个宾语从句 do you doubt that he will win 为什么用that为什么不用 if 或whether are you sure ()they will come为什么天 that ×而不是if ×或whether or not 直接引语变间接引语时、直接引语如是是翻译疑问句、就要改成whether 或if 、那怎样区分是用whether 或if i think造句用that,whether,if 宾语从句什么时候用if,whether,that 介词之后的宾语从句,不可用which或if连接,要分别用what或 whether,为何? The question came up at the meeting ____ we had not enough money for our research.有that,what,if,whether可选答案选whether,我想问为什么不能选if或what有的解析上选that， Is it true?Dark make people look thinner?(合并为一句）老师说It is true that(后面照抄）可是一般疑问句在改为宾语从句时,不是要先加if或whether吗?请说明理由. 一般疑问句作宾语从句时if可否全部替换为whether?一般疑问句作宾语从句时用连接词if或whether,那么if可否全部替换为whether? Check that the person can breathe. 本句中的that是否可以换成if或whether请说出回答的根据(如:某词典) He is very young.Iam not sure ____he can finish the work alone or not.A .how B .that C .whether D .if为什么不选D呀！短语有whether……or not,whether or not和if……or 有if……or not。whether或if均可表示“是否”的情况如 Whether if that的用法. do you think ____ I should attend the meetinga whetherb ifc howd that可是不太明白为什么不选whether 或 if there is no doubt that he will come to help usthat 为什么不能用whether 或 if他是否会来帮助我们是毫无疑问的 I asked that he was really happy.如果是这类翻译——“我问他是否真的快乐。” 不是应该由if 或whether引导吗？ 用that if/whether 各造句5个. 用that.if.whether.疑问代词各五个造句快!