one is but two_____.

one is but two_____. My brother bought two_____(mouse),one is for his computer. One is but two are. There is no one but There is no one home but you there is no one but longs to No one is noble but me There is no one but me."but"的问题 this book is ( )that one ,but ( )than that one . Ramnce is one ting ,but marriage is quite another thing Number One is right,but Number Two is f＿ one's life is limited,but leaning is