单项选择题

The US border with Canada is the ______ in the world.

A．longest coastal border
B．longest defended border
C．longest undefended border
D．longest undefined border
<上一题 目录 下一题>
热门 试题

单项选择题
According to the news item the volcano had been dormant for about ______.
A．45 years
B．60 years
C．30 years
D．200 years
单项选择题
As one of the world's most active volcanic zones, Kamchatka is close to ______.
A．the Arctic Ocean
B．the Pacific Ocean
C．the Atlantic Ocean
D．the Black Sea
相关试题