【题目】When first to ___________ the market, these products enjoyed great success. ( )
A.introducing B.introduced
C.introduce D.being introduced
【答案】C
【解析】
本题考查动词不定式的用法。根据When first to the market，these products enjoyed great success. 可知当首次引入市场时，这些产品获得了巨大的成功。first to do sth表示第一次做某事。故选C。
