离心式压缩机在临界转速中的共振主要是由（）引起的。
A、自振
B、喘振
C、强迫振动
D、管线振动
参考答案：A, C
关于病理性钙化的描述，正确的是
A．HE染色时呈蓝色颗粒
B．营养不良性钙化多见
C．转移性钙化多发生于肾小管、肺泡和胃黏膜
D．营养不良性钙化多见于变性坏死组织
Please find another hotel for me, ________ than this one. [ ]
A. more near and comfortable
B. nearer and comfortable
C. nearer and more comfortable
D. more near and more comfortable
