I must do my best not to try my best和I must do my best not try my best哪个对?

No matter what I do,I will do my best I must do my best not to try my best和I must do my best not try my best哪个对? My English is very poor.I must _(do) my best.怎么填 I WILL DO MY BEST 请问 I DO MY BEST 请问 I DO MY BEST I already do my best! i must do my best.try to make difference什么意思? I feel I must spare no efforts to do my bit. i fell i must spare no efforts to do my bit意思 What would I do if my best friend Tony r___(said no) to help me? 选择：-Can I tell my best friend about it?-No,Ido not want anyone else to know.You( ) tell anyone.-Can I tell my best friend about it?-No,Ido not want anyone else to know.You( ) tell anyone.A,will notB,must notC,do not have toD,need notmust not不 修改错误Must I do my homework now?No,you mustn’t.__________ Must I do my homework?的否定回答是用“No,you needn't.”还是“No,you mustn't.” （ok,i will do my best! Must I do my homework now No,you .you can do it later 填donnot have to 为什么 SO i must believe i can and i wil l try my best face up with smile to life no matter what happen Do my best to do what I want to do!