Some people argue using ____________ nature to meet our own needs may spell disaster, unless we start to look around and understand how _________ clean environment benefits us all.

A．/; a

B．the; the

C．the; a

D．a; a

以下哪一项不是常用的调剂工具( )

A．戥称

B．分厘戥

C．研钵

D．铁碾船

E．天平