休克早期时下列临床表现中哪一项不存在（）
A.神志改变
B.面色改变
C.脉搏细速
D.血压下降
E.少尿
参考答案：D
She showed the visitors around the museum, the construction________had taken more than three years.
A．for which
B．with which
C．of which
D．to which
焊缝金属中氢的危害有（）。
A.氢脆
B.白点
C.产生气孔
D.引起冷裂纹
E.引起飞溅
F.产生夹杂
