A:from whom; by whom
B:to whom; who
C:from whom; who
D:to whom; by whom
小杜同学在长江边捡到一块漂亮的鹅卵石,他用天平和量筒测量鹅卵石的密度.
紧急情况下,任何血型的人都可以少量输入( )