机动车发生碰撞时座椅安全带主要作用是什么？

A．减轻驾乘人员伤害

B．保护驾乘人员腰部

C．保护驾乘人员颈部

D．保护驾乘人员胸部

Fair and(1) competition in government procurement around the world is good business and good public policy. Competitive pricing, product(2)and performanceimprovements result from competitive practices and help ensure that government authoritiesget the best (3)for the public they serve.

空白（1）处填（）

A.open

B.continue

C.dependent

D.reliable