I don′t know if he come this afternoonI don′t know if he come this afternoon.请问该错误的原因是什么,该怎么改呀?

I don't know if he ____(be) free tomorrow. I don't know if he ____ ( come ) I don't know if he will come tomorrow i think he if he free I don't know if he_.if he _home,please let me know.(return). I don't know if he __tomorrow.if he ___piease let me know.A.comes,comes B.will come,comes C.will come,will comewhy? I don't know if he ___.if he ____,please tell me .(come) 求解两题1、I don't know if he ____ to Kate's birthday party.He's sure to go if he ____.1、I don't know if he ____ to Kate's birthday party.He's sure to go if he ____.A.goes；knows B.will go；knows C.goes；will know D.go；know2、Do you know I don't know if he will come tomorrow.为什么要用if 不能用whether i really don't know if he _____tomorrow.if he_____,please give me a ring(come) I don't know if Mr.Green_______(come) tomorrow,but I will let you know if he _____(come) tomorrow I don't know if ny uncle If he I will be very happyA comes ；will comeB will come ；will come C comes； comesD will come；comes I don't know if he ___(come) tomorrow.If he ____(come),I'll tell him about it I don't know if he __ to the movie this evening.If he wants,so ___ I. 英语翻译i don't know if i should i don't know if i should i don't know if i should i don't know if i should i don't know if i should i don't know if i should i don't know if i should i don't know if i should i don't know if i should i don't know don't know if he __.If he__,I will tell you为什么A.will come ,comes B.will come ,will come C.comes,comes I don′t know if he come this afternoonI don′t know if he come this afternoon.请问该错误的原因是什么,该怎么改呀? I don't know what he needs i don't know if he comes next week哪里错了