—Shall I talk to Mr. White in English or in Chinese?

—Do as you please.He knows       .

A．all

B．neither

C．both

D．any

下列情况中使呼吸运动增强最明显的因素是

A．PCO2升高

B．PO2下降

C．H+浓度增加

D．非蛋白氮增多

E．乳酸增多