题目

---Where is Kate? ---She_________toLondon. She ________ there yesterday. A.has been to,went              B. has gone to, went C. went, went                    D.went, has been to 答案：B把铝粉和氧化铁粉配成铝热剂，分成两等份．一份在高温下恰好完全反应后，再与足量盐酸起反应；另一份放入足量的烧碱溶液中充分反应．前后两种情况下生成的气体的质量比是（　　）A．1：1B．2：3C．3：2D．28：9