{ba=0a=a
(Ⅰ) 求BD长;
(Ⅱ)当CE⊥OD时,求证:AO=AD.
No one hopes the two countries will be at ________ war, because ______ peace is what everyone wants.
甲、乙两图中,电阻R1为10Ω,电源电压为10V.开关S闭合后: