题目

She gave the students a lesson ____ Mr. Wang.A．insteadB．instead ofC．instead onD．instead in 答案：B解析:instead of代替。有a L乙炔和乙烯的混合气体在催化剂存在的条件下与足量H2发生加成反应消耗1.25a L H2,乙烯和乙炔的体积比为(    )A.1∶1                 B.2∶1                C.3∶1                D.4∶1