题目

_______ did he tell his wife ________ he wished to do A. That...what  B. What...that          C. Where...which    D. Which...where 答案：B下列操作中，能鉴别空气、氧气和氢气3瓶气体的是A．观察气体颜色 B．插入燃着的木条C．闻气体的气味 D．倒入澄清石灰水