人们在视线内的一切东西都具有某种颜色，所以视觉就是一种对颜色的感觉，是通过视觉器官来辨认的。
参考答案：错
His whole school education ________ only half a year, because his family was very poor.[ ]
A．added up
B．added up in
C．added up to
D．was added up
侵蚀性葡萄胎、绒癌最重要的治疗手段是（）
A.手术
B.放疗
C.化疗
D.中药
E.免疫治疗
