L-C型制动梁弯角边缘在制动时受交变载荷的作用，在质量缺陷处边缘产生裂纹或折断故障。
参考答案：对
It is reported that a small plane from South Africa crashed (坠毁) northwest of Changsha
_______ May 28, 2004.[ ]
A. on
B. in
C. to
D. at
开展批评与自我批评应该运用以下（）方式。
A.团结—批评—团结
B.批评—团结—批评
C.批评—团结
D.团结—批评
