所谓“发现”，则是指从（）的转变。
参考答案：不知到知
It was hard for him to learn English in a family, in which _____ of the parents spoke the language.
A．none
B．neither
C．both
D．each
某种烷烃11克完全燃烧，需标准状况下氧气28升，这种烷烃的化学式是[ ]
A．CH4
B．C2H6
C．C3H8
D．C4H10
