First, their anxiety about the event should decrease because of expecational knowledge. Anxiety is that uneasy feeling that you have when you are not sure about what will happen. An ESL student might feel this way when they have to engage in a relatively complex information gathering task.
I learned this many years ago while teaching a group of students in a beginner ESL class. It was one of the first unsupervised courses that I taught after completing my pre-service English as a Second Language teaching qualification. There were only 6 students in the class, and all of the students had only been in Vancouver for about a week. One student had even just arrived the day before.
Can you imagine the feelings of anxiety this student might have had?