零件疲劳导致了其（）性能的变化。
A、力学
B、使用
C、化学
D、机械
参考答案：A
Gd-DTPA增强主要是因为（）
A.缩短T1弛豫时间
B.信噪比下降
C.空间分辨率下降
D.对比度下降
E.信号均匀度下降
Project success depends on a number of interrelated factors, including time, cost, and scope control. However, the success of any project depends primarily on ______ .
A．customer acceptance
B．customer satisfaction
C．customer compromise in defining its needs
D．exceeding customer requirements through gold-plating
