For Mac OS users, there is a system setting that may not allow you to tab onto several types of elements in a web page. To change this setting:
Reading Classes are 9:20-10:27, 10:27-11:33, 11:33-12:40
Lunch 1:00-1:30
English classes are 1:10-1:55, 1:55-2:40, 2:40-3:25