BBC在线收听下载:伊斯兰国极端组织发布斩首威胁视频

短语讲解：

1. It would also increase pressure on President Obama to go after the militants at their base in Syria, which he has been reluctant to do.

go after 追逐，追求
例句： I don't go after fame or money. 
我不追名逐利。 

2. The UN's coordinator for the response to the crisis David Nabarro said the world needed to do more.

response to 对…的反应
例句：What's your response to the criticism?
您怎么回应受到的那些批评？

3. Civilians have been fleeing the area, but Ukrainian forces say they remain in control of the facility.

in control of  控制，管理
例句：He was in control of the car. 
他负责这辆小汽车。 

4. Moscow said earlier it was beefing up its military strategy because of Nato plans to deploy a rapid reaction force in the countries.

because of 因为，由于
例句：The journey was slow because of continual stops. 
由于常常停下来，所以行程很慢。