VOA慢速英语:联合国考虑对朝鲜实施石油禁运

critical – adj. very important, without which nothing can be done

leverage – n. influence that can be used to get a desired result

alienate – v. to cause to become isolated or apart from the group

walk a fine line – idiom to try to deal with two opposing issues or sides to avoid conflict

flexibility – n. the quality of being able to adjust or make small changes

exception – n. a case where a rule does not apply