VOA慢速英语:CIA: Islamic State Group Has More Fighters than Thought

estimate – n. an opinion about a value, size or amount using less than complete information

militant – v. showing a desire to use extreme and sometimes forceful methods; n. someone active in trying to cause political change, often by the use of force or violence

coalition – n. forces, groups or nations working together

shocked – v. caused to feel sudden surprise or fear

executed – v. killed