题目

燃气热水器中燃气不充分燃烧易产生CO气体，下列关于CO的说法错误的是：( ) A . CO气体有毒，可危害人体健康 B . CO可用于冶炼金属 C . CO可以燃烧，可作燃料 D . 在煤炉上放一壶水就能防止CO中毒 答案：D The employment rate has continued to rise in big cities thanks to the efforts of the local governments to increase___________.A. them B. those C. it D. that