题干
Cathy was born blind（天生是盲的）, so she has __________ seen our beautiful world.
A：often
B：sometimes
C：seldom（很少）
D：never
答案(点此获取答案解析）
D
Cathy was born blind（天生是盲的）, so she has __________ seen our beautiful world.
A：often
B：sometimes
C：seldom（很少）
D：never
5Z(g) 
，在某温度时X的浓度随时间变化的 曲线： ( ) 
