A combustible gas indicator meter is calibrated to read the percentage of（）.

A.vapor to oxygen

B.the flammable limit concentration

C.the autoignition concentration

D.the lower explosive limit concentration

纤维素性血栓主要发生在（）.

A．下肢深静脉 

B．左心耳 

C．微循环 

D．心室壁瘤内 

E．门静脉