存折存单换发时，错误的是（）.
A、原帐号发生更改
B、原支取方式为密码的必须输入密码
C、需经过授权
D、不收取手续费
参考答案：A
— You should have told her about the meaning of the gesture.
— I meant ______, but I had some unexpected guests.
A．to do
B．to have
C．doing
D．doing so
氢能源具有来源广、无污染等优点．火箭发动机用氢作燃料是因为氢的______很大，氢气的热值为14.3×107J/kg，完全燃烧0.5kg的氢气可放出______J的热量；若一罐氢气用去了一半，则剩余氢气的热值______（填“大于”“等于”或“小于”）14.3×107J/kg．
