如图，∠A=∠D=90°，AB=DE，BF=EC．求证：Rt△ABC≌Rt△DEF．

若定义在R上的函数f(x)满足$f\left(1-x\right)=f\left(x+3\right)$,且$\left(x-2\right)f^{\text{'}}\left(x\right)$<0,a="f" (${\log }_{2}5$),b="f" (${\log }_{4}15$),c="f" ($2^{0.5}$)，则a,b,c的大小关系为(        )

如图所示，有一水平方向的匀强电场，场强大小为9000N/C，在电场内一水平面上作半径为10cm的圆，圆上取A、B两点，AO沿E方向，BO⊥OA，另在圆心处放一电量为10^﹣8C的正点电荷，则A处场强大小E_A为零．____ （判断对错）

根据句意和汉语提示，在空格中填入正确的单词 。
⑴North points up on a ____  (地图).
⑵There is a tall tree____  (在。。。。。。的后面) the teaching building.
⑶____ (没有什么) is difficult to the men who will try.
⑷____  (十月) 1st is the National day of the PRC.
⑸He always ____ (抄写) new words on pieces of paper and reads them aloud.
⑹It's____ (礼貌 ) to be quiet in the library.
⑺No one can____ (成功) without any hard work.