While riding in the street, _______________________________.

A．someone called me from behind

B．I heard my name called

C．my bike broke down

D．an old man knocked down

对目前正处于滑动阶段的土坡，其滑动带的土为黏性土，对这种土进行剪切试验时宜采用下列哪一种方法（）

A.多次剪切 

B.快剪 

C.固结快剪 

D.慢剪