题目

 — I am surprised to hear that Russian President Putin and Lyudmila Putina have ________.    — So am I. They seemed very happy together when I last saw them on TV.    A. broken down     B. broken up       C. broken into       D. broken out 答案：B汽油的热值是4.6×107J/kg，完全燃烧21kg汽油放出的热量是多少？这些热量的一半被水吸收后，水温升高了23℃，这些水的质量是多少千克？