寿命周期成本最佳化的途径是在资产具备规定性能的前提下,要尽可能使( )达到最少。
A.设置费
B.维持费
C.安装费
D.设置费和维持费的总和
参考答案:C
Jane _______ the piano when she was five.[ ]
A. picked up
B. looked up
C. sat up
D. began to learn
疟疾流行病学史是指曾于()在疟疾流行区住宿、夜间停留或近二周内有输血史。