I don't think _________ possible to master a foreign language without much memory work.

A．this

B．that

C．its

D．it

文物：建筑：故宫。（）

A.调料：作料：花椒

B.服装店：网店：淘宝网

C.背包：皮包：牛皮

D.脊椎动物：水生动物：鲤鱼