CRTSII型板式无砟道床侧向挡块伤损有（）
A.裂缝
B.与底座板粘连，引起侧向挡块混凝土伤损
C.弹性限位板失效
D.离缝
参考答案：A, B, C
It is _____ he often fails in exams ________ makes his parents worried about him.
A．what; that
B．that; what
C．that; that
D．/; that
胺基化工艺参数包括（）
A.反应釜内温度、压力
B.反应物质的配料比、气相氧含量
C.以上都是
