一/32_____ a scientist is being deliberately informal,he will tend to speak like abook when he is explaining science.A.WhenB.WhileC.If D.Unless

Question

一/32
_____ a scientist is being deliberately informal,he will tend to speak like abook when he is explaining science.
A.When
B.While
C.If
D.Unless

Answer 1

选D
除非一个科学家故意让人看起来不那么一本正经,否则在他解释科学的时候总是跟书一样严肃.
其他3个选项都不对