I think that it's a useful to learn a foreign-language.I think ____ _____ a foreign language ____ _____

Is that true that it's hard to be a person?I don't think so! I think it's a bad It's a pity that I didn't think of ringing you earlier是什么意思 You think it's a joke,then that it is. that's one way to think of it,i guess Who’s that?-I think （ ） Bill A.his B.she’s C.it‘s 选哪个?.. it's 11:00.i think you should go now.---()A.all right B.think you C.that'all right D.that's right I do that sometimes ,I think it (h )a lot what's that over there?It's a cat,I think.Perhaps it's Li ping's.Let's go and ______. Think it over ,I think it's I think __our duty to keep our evirionment clean an tidy.A.this B.that C .it D.it's I think ------silly------you not to forgive others for their mistakes.A it,for B it's of C that's of D it's for I think that it's a useful to learn a foreign-language.I think ____ _____ a foreign language ____ _____ it's a nice day .i think s( ) I think it 's full. means ( ).A:I think it's empty B:I think it's not emptyC:I don't think it's full D:I don't think it's empty 急 Do you think it`s ture that there are a ( ) I think that I just throw it all up later,but it think it's just high metabolism or maybe. 并能说明原因I think __important__we should learn Enlish well.A：is,that B：it,that C：it's what D：it,what