I don’t think possible to master a foreign language without much memory work.A. this　B. t

问题补充：

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

A. this

B. that

C. its

D. it

答案：

A. this

B. that

C. its

(答案→)D. it

解析： it作形式宾语，代指后文的不定式。