A．空气
B．地球
C．高速喷出的燃烧气体
D．月球
答案：C
He is looking for another job because he feels that nothing he does ______ his boss. [ ]
A. serves
B. promises
C. satisfies
D. supports
下图为测定反应速度开始和结束时手的位置。据此推算，你的反应速度约为（ ）
A．1 cm
B．3 cm
C．4 cm
D．5 cm
