The 2010 Shanghai World Expo is intended to achieve our common goal: ________world that is safer, cleaner and healthier than ________ one we’re living in.

A．the; the

B．a; /

C．a ; the

D．the ; /

具有降肋助呼气作用的是（）

A．肋间外肌和肋间内肌

B．肋间内肌和腹前外侧肌群

C．肋间内肌和膈

D．膈和腹前外侧肌群