题目

     The life of George Washington was characterized by a high regard for punctuality (守时). For him, being on time was a way of showing  41  to others, and he     42  to be treated with the same level of respect  43 .        Once Washington asked a man to bring some  44  he was interested in buying at five in the morning.  45 , the man arrived fifteen minutes late. Washington’s groom (马夫) told the man that the general (将军) had been  46  there at five, but had now moved on to other business. Washington said that he wouldn’t be able to  47  the h如图，在长方体ABCD-A1B1C1D1中，已知AB=4，AD=3，AA1=2．E、F分别是线段AB、BC上的点，且EB=FB=1．（1）求直线EC1与FD1所成角的余弦值；（2）求二面角C-DE-C1的平面角的正切值．