I think more than one --- that half of the students--- here

I think more than one ___ that half of the students___ here from China A.konws；are B：know areI'd appreciate___ if you could turn the radio down.I‘m doing my homework.A.you B that C this D itIt seems that the aged people ___ the H7N9 more easily from the recent cases.A pick up B mix up C set up D use up并说明理由