In the past few years, sea ice ____ in the Arctic as a result of global warming.

A．had melted

B．has been melting

C．melted

D．is melting

根据《SDH光传输系统工程验收规范》，机房内严禁存放（）等危险物品。

A.易碎

B.易燃

C.易辐射

D.易爆