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

俄国现实主义文学的奠基石是（）。

A.《死魂灵》

B.《当代英雄》

C.《上尉的女儿》

D.《叶甫盖尼·奥涅金》