题目

如图，在Rt△ABC中，∠ACB=90°，D、E、F分别是AB、BC、CA的中点，若CD=5cm，则EF=   cm．                (第16题)                        (第17题)                (第18题)  答案：5解析:略  Leeds CastleOne of the most popular places of interest in BritainOpening timesOpen all year round except(除了) 7th and 8th November and Christmas Day（25th December）2014．1 April to 30 September 2014Open：10:30 am—5:30 pm; Gates close at 6pm1 October 2014 to 31 March 2015Open：10:30 am—4 pm ; Gates close at 5pmPricesAdults：￡16.50Students：￡9.50Children under 4：free1.Leeds Castle is closed on _________．A.7th January B.8th AugustC.25th December D.1st April2.John and Mary will take their three-year old son to Leeds Castle．How much should they pay?A.￡33． B.￡16.50． C.￡26． D.￡9.50．3.What time does Leeds Castle close on 29th October?A.6 pm． B.6:30 pm． C.5:30 pm． D.5 pm．