介绍:
词汇
attack 袭击
injured 受伤
vulnerability 弱点
doorstep 门阶
extremist 极端主义者
enclaves 飞地（不懂请百度）
意群
The Brussels attacks
with more than 30 dead and hundreds injured
show yet again the vulnerability of Europe,
Which is on the doorstep of extremists-held enclaves
in North Africa
and the Middle East.
