course line selector

例句：

1. 1. The course lineselector on the computer screen allows studentsto quickly access their courses.
   电脑屏幕上的课程线选择器让学生能够快速访问他们的课程。
2. 2.The teacher used the course line selectorto select the correct answer for the quiz.
   老师使用课程线选择器为测验选择了正确的答案。
3. 3. The student was frustrated because hecouldn't find his course lineselector in the crowded classroom.
   学生因为找不到他的课程线选择器而感到沮丧，教室里人很多。