Pay your gas bill as soon as possible, or the gas will be ______.

A．cut off

B．cut out

C．cut up

D．cut down

“西部开发，生态先行”是因为[     ]

A．人类反思了传统发展模式的弊端    

B．搞好生态建设是实现可持续发展的前提

C．西部人口少，保护生态环境的人少      

D．西部生态环境条件好，需保持