He found himself       by a crowd of excited people and       to escape.

A．surrounded; trying

B．surrounding; trying

C．surrounding; tried

D．surrounded; tried

下列构件中哪一种超过承载能力极限状态？（）

A.构件在荷载作用下产生较大变形而影响使用

B.构件在动力荷载作用下产生较大的振动

C.构件受拉区混凝土出现裂缝

D.构件因过度的塑性变形而不适于继续承载