如图，△ABC中，AB=AC，BC=12cm，点D在AC上，DC=4cm．将线段DC沿着CB的方向平移7cm得到线段EF，点E，F分别落在边AB，BC上，则△EBF的周长为cm．
函数f(x)＝sin(ωx＋φ)(x∈R，ω＞0，|φ|＜)的部分图象如图所示， 如果x1，x2∈(－，)，且f(x1)＝f(x2)，则f()等于( ) A． B．
中国人民银行授权中国外汇交易中心公布，银行间外汇市场美元等交易货币对人民币汇率（100单位外币兑换的人民币）： 时间美元日元欧元 2007年2月7
如果实数满足等式，那么的最大值是 （ ） A. B. C. D.
We had wanted to come to see him, but we ____ no time. A. had B. had had C. would have D. would have had
PART THREE READING COMPREHENSION Directions: Read the following three passages. Each passage is followed by several questions or unfinished statements. For each of them there are four choices mark
．如图，AB是⊙O的弦，OD⊥AB于D，交⊙O于E，则下列说法错误的是( ) A．AD＝BD B．∠AOE＝∠BOE C.＝ D．OD＝DE
已知：①N2（g）+2O2（g）═2NO2（g）△H=+67.7kJ•mol﹣1，②N2H4（g）+O2（g）═N2（g）+2H2O（g）△H=﹣534kJ•mol﹣1．下列关于肼和NO2反应的热化学方程式中正
