Question 4 is based on the news report you have just heard.

News Report Two

    The Tunisian government said on Monday that 45 people have been killed after gunmen attacked a town near the border with Libya. 

    The Interior and Defense ministries said that the Tunisian government（3）has closed its two border crossings with Libya because of the attack. 

    The Tunisian military has sent reinforcements and helicopters to the area, and authorities have been hunting several attackers who were still at large. 

    The violence came amid increasing international concern about Islamic State extremists in Libya. Officials of the Tunisian government are especially worried after dozens of tourists were killed in the attacks in Tunisia last year. 

    Defense Minister Farhat Horchani said last week that German and American security experts were expected to come（4）to help Tunisia devise a new electronic video supervision system on its border with Libya. 

    Tunisia was targeted last year by three attacks that left 70 people dead and were claimed by Islamic State.

4. What were German and American security experts expected to do in Tunisia?

解析：D。该题目为细节题。问题是：德国和美国安全专家会在突尼斯采取什么行动？根据问题关键字“German and American security experts”定位文章出处：Defense Minister Farhat Horchani said last week that German and American security experts were expected to come to help Tunisia devise a new electronic video supervision system on its border with Libya.德国和美国安全专家会来帮助突尼斯在其与利比亚的边境建立一个新的电子视频监控系统。选项D）Devise a monitoring system on the Tunisian border with Libya，与原文内容一致程度最高，其中monitoring 和 video-supervision system 都有监控的意思，两者为同义替换，monitoring是上位词。因此，此题目正确答案为D。