肾上腺素与局麻溶液的浓度比应为（）
A.1：40000
B.1：80000
C.1：200000
D.1：300000
E.1：400000
参考答案：C
While auscultating heart sounds of a client with heart failure, the nurse hears an extra heart sound immediately after the second heart sound (S2). The nurse should document this as （）.
A．a first heart sound (S1).
B．a third heart sound (S3).
C．a fourth heart sound (S4).
D．a murmur.
裂解炉排烟温度过高，过低有什么缺点？
