Fill in the Blanks C17U2 Homework BOnline version Complete the article with prepositions by Modern English 1 Teachers have expressed concern the effects TV some of their students . They believe there is a link the fact that some students fall asleep in class and the increase the amount of TV they watch . Being so tired obviously has an influence their ability to learn , and an impact their behavior . Staying up late watching TV or playing video games is one cause teenagers' tiredness . this is not just because they spend less time in bed . The results several studies suggest another reason students' lack of sleep ; after several hours watching a screen , it can take a long time for the mind to relax and " switch off . " This means that even if they go to bed at a reasonable time , they are unable to fall asleep immediately .