颈外静脉怒张伴收缩期搏动见于（）。
A.三尖瓣关闭不全
B.三尖瓣狭窄
C.二尖瓣狭窄
D.二尖瓣关闭不全
E.主动脉瓣关闭不全
参考答案：A
为了防止奥氏体不锈钢因连多硫酸引起的应力腐蚀，通常在停工后用（）浓度的碳酸钠溶液进行碱洗中和。
A、0.5%～1%
B、1.5%～2%
C、4%～5%
D、6%～8%
The photo brought me back to the memory of the time in Qingdao, _____ I spent my summer holiday by the seaside with my friends.
A．that
B．when
C．which
D．what
