When to the market, these products were very popular.
A. introducing
B. introduced
C. introduce
D. being introduced
网友回答
A. introducing
(答案→)B. introduced
C. introduce
D. being introduced
解析：
试题分析:考查非谓语动词。由结构可知When to the market, 在句中做状语，而逻辑主语these products和introduce之间是被动关系， being introduced表示正在进行的被动，不合句意，所以B选项正确。补充完整后为：when they were introduced to the market。句意：当被引进到市场上的时候，这些产品非常受欢迎。