I don't know ____ it is meant for.A.that B.whom C.how D.why

I don t know how I should do it同意句I don t know how ____ ____ it Oh,it's you. I'm sorry I ____ (don't) know you ____ (be) here. What does it _____?Sorry,I don't know its ____,eWhat does it _____?Sorry,I don't know its ____,either. 填空:I don't know what ______ ______ .I don't know where ____ ____. I don't ____(介意) about it. I don't know when we shall start.(改为简单句) I don't know ____ ____ ____. —The house was torn down.—Really?I ____ it.A.don't know B.haven't known C.didn't know D.hadn't known Don't you know my telephone?____,I don't know.这是一句反意疑问句吗,怎么填? I don't know what I should take.(改为同义句）、 I don't know what ____ ____ I don't know if he ___(come) tomorrow.If he ____(come),I'll tell him about it I don't know what it means = I don't know _________. i don't know how to do it句型转换i don't know[ ][ ][ ]do. I don't know if he ____(be) free tomorrow. I don't know if he ____ ( come ) sorry i don't know ,____ not call him I don't know. I don't know if I will depart for another cityI don't know ____ ____ depart for asnother city. How old is he? I don't know （变为同义句）I don't know ____ ____