Many people in the west make a rule to buy Christmas presents for their relatives and fr

问题补充：

Many people in the west make a rule to buy Christmas presents for their relatives and friends. A. thisB. itC. thatD. them

答案：

it形式宾语，真正的宾语是后面的动词不定式。make…a rule使……成为习惯或规矩。