mix用英文怎么解释啊?

题目

mix用英文怎么解释啊?
She was busy mixing butter and flour .She was _____.
A)joining them
B)uniting them
C)unifying them
D)putting them together
我先选的是C,但是答案是D,我觉得不理解,为什么不是C而是D呢?

答案

D
mix,这个句子是说搅拌的意思,把黄油和面粉混合在一起,所以是放他们在一起的意思.
unify 则是统一的意思,比如说统一国家之类的,用在比较大的地方.