这句话中为什么不能用if?I do not know wheather he will come to our party.I do not know wheather he will come to our party.我们老师说因为前面有not所以不能用if,但我好像没听过啊.谁能具体解释下?

这句话中为什么不能用if?I do not know wheather he will come to our party.I do not know wheather he will come to our party.我们老师说因为前面有not所以不能用if,但我好像没听过啊.谁能具体解释下? .I have no idea _____ we can do with these waste materials为什么不能用whether?答案是what do you agree 为什么不能用Yes,I do 回答? Are you going to see that film tomorrow?i have no idea.If you don't().If you do,()A.nor shall i 'so shall i B.nor do i 'so do i 为什么选A不选B? do you think if i should take part in sport?为什么错了?是为什么应该用that而不能用if！ it ,that 的区别I'm not sure if I'll type my paper myself; I have more important things to do than that.这个句子中为什么不能用 it 代替that I do not know whether he wil come to our party.中为什么不要能用if?解释具体些, 关于if i want和if i wanted区别i would have to take unpaid leave if i want to study full-time.you could do that in eighteen months if you wanted.在这两句话中,为什么一个用了if i want而另一个却用了if i wanted,是不是i Do you mind if I take this seat?-___.A.No,of course not B.No,you can’t take itC.Yes,sit down,please D.Yes,take it,please这句话什么意思?选哪个,为什么? If he is not at home ,I will call him tomorrow为什么只能用will不能用be going to do sth? 回答do you mind 为什么不能用yes,please?Do you mind if I open the windows?____A Yes,pleaseB Go ahead回答不是通常先回答个yes,或者no么,A怎么不行了?应该是NO，please 感觉没错哇。 Do you like dogs?No,I like fish.为什么第一句话中的dog加s,Do you like dogs?No,I like fish.为什么第一句话中的dog加s,第二句话中的fish不加s? A:I'm going to the post office,for I have a letter to post B: But I have no letters to be posted.这其实是个选择题,第二个B 说的句子中为什么不能用 to post呢,上面那个句子不就是to do 不定式吗?老师说第二个桔子 英语,为什么不能用IF? 关于whether与ifI have no idea whether to visit my grandparents this Sunday.这句句子当中为什么只能用whether,不能用if?请详细回答```` 我搞不懂这句话的用法?If( asked ),please help him(do ).能不能用asking?后面的可以用to do I have been missing you very much after I went to college a year ago.这句话中为什么after不能用,要改为since?二者如何区分? I don't know if he will come tomorrow.为什么要用if 不能用whether