According to a new study by a French university, learning second language can lead to in

According to a new study by a French university, learning second language can lead to increase in your brain power.
A. a; the
B. a; an
C. the; the
D. the; an

A. a; the(答案→)B. a; anC. the; theD. the; an解析：考查冠词用法。序数词second前用不定冠词，不表示顺序，而是表示“又一，再一”的意思。另外，根据本句含义，脑力的增强“increase in your brain power”，此处的increase不是特指，应该用不定冠词。句意：根据一个法国大学的调查，学习另一种语言可以导致脑力的增强。选B。

就是这个解释