Our math teacher ______ in our school for 20 years and he ______ here when he was 23 years old. [ ]

A. has taught, has come

B. taught, comes

C. taught, came

D. has taught, came

肺活量是反映在一次呼吸中的肺的（　　）

A．容纳气体内的最大量

B．通气的能力

C．最大通气能力

D．能更换肺内全部气体