如图，在梯形ABCD中，AD∥BC，∠B=60°，∠ADC=105°，AD=6，且AC⊥AB，求AB的长．
—Did you wait for him very long? —No, it seemed just few seconds _____he came back. A. before B. when C. that D. after
《人民日报》在《为科技下乡进一言》一文中指出，和在乡镇搞一些热热闹闹的摆桌咨询活动相比，带着自己的科技成果进村入户要艰苦得多。要让科
《陋室铭》中“ ， ”是与“孔子云：‘何陋之有’”相呼应的核心句。
下列数中：﹣8，2.7，0.66666…，0，2，9.181181118…是无理数的有（ ） A．0个 B．1个 C．2个 D．3个
如图，导热性能极好的气缸开口向下，内有理想气体（即为可以不考虑气体的分子势能的气体），缸内活塞可自由滑动且不漏气，活塞下挂一个水桶，
It was reported today that in China, 56% of people who write blogs(博客) do so as a personal diary and 83% use their blogs for sending messages to friends. It was also found that there is a strong E
已知函数在单调递减，则实数的取值范围是（ ） A． B． C． D．
