模态试验分析
参考答案：
为确定系统模态参数所作的振动试验分析。通常，先由激励和响应关系得出频率响应矩阵，再由曲线拟合等方法识别出模态参数。
—I've got something weighing on my mind. Could you give me some advice?
—________. Tell me all about it and I'll do what I can.
A．Don't mention it
B．No way
C．No problem
D．Forget it
实验室要测一油品凝点，预期凝点-2℃，则冷浴温度为（）。
A.-5℃
B.-12℃
C.-9℃
D.-20℃
