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

A. this B. that   C. its     D. it

〖答案与简析〗选D。测试 it 用作形式宾语，代替由不定式、动名词或从句表示的真正宾语。当宾语有自己的补足语时，用it作形式宾语，真正宾语放在补足语之后。常用这种句型的动词有think , make ,  find , feel , consider 等。