吸氧流量为3L／分，氧浓度为（)。

A.1L

B.2L

C.3L

D.4L

A.29%

B.33%

C.37%

D.41%

E.45%

A.29%

B.33%

C.38%

D.41%

A.12%

B.61%

C.40%

D.33%

A.33%

B.39%

C.24%

D.30%

A.29%

B.33%

C.37%

D.41%

A.25%

B.29%

C.33%

D.37%

E.41%

A.30%

B.31%

C.32%

D.33%

A.25%

B.29%

C.33%

D.37%

E.41%