27.2,1.: 2.(): 3.(): 4.(): 5.():,1?,2,.紵,绯. ,:,:,.,14.,?,OBOBABABOB, OABOAB, ABOABO90, OABOAB,OBOBABAB,137,1OB1AB2AB274OB.,2:ABCABBCEECBCBCAED,BD120DC60EC50AB,A,D,C,E,B, ADBEDC,ABCECD90, ABDECD, 100,BD120DC60EC50AB(),2:ABCABBCEECBCBCAED,() AD EDEADBBCDEEACDE , BC, BD, AB,DE120BC60BD50AB,𲢽,3.AB=8mCD=12m,BD=5m.1.6mLC?,F,A,H,B,C,K,D,F,A,H,B,C,K,D,E,G,L,4.ABPC,AB PCDEMNABNPCNAABP,1C,2 1C CM,1.,1.83,60,?,36, ,2.,1m,16m,0.5m, m,8,3.AB,C,ACABACDBCE,DEACAD=35mDC=35mDE =30m,AB?,455015仹 ,5. 5h.(),A,D,B,C,E,0.8m,5m,10m,2.4m,6a25cm xAB濨ACBDOA:OC=OB:OD=3CD=7cmx,O,xABAB,7.ABCDCBCD=4m,BC=10mCD3012,8. AB8MEBEDADE=2.8MCD=1.6M,C,D,E,A,B,A,B,C,8. 2.40MCD2.80M1.47M, 0.1M, ,F,D,C,E,B,A,? 2. !?,1. , . ,! 2. 򵥵.,