Even though extensive reading should be done mostly for fun and general language development, giving the students a choice of activities or tasks to complete while reading their book and / or after finishing the book will help you keep them accountable for their reading and will let you know if they understand the gist of what they are reading as well.
Extensive reading is the use of interesting texts for general language development and comprehension. It differs from intensive reading in that students do not get tested on all the details of the plot and do not stop on every new word. The aim of having your students do extensive reading is mainly for them to practice the language, develop their overall comprehension and be exposed as much as possible to the language they are learning.
New teachers will find that ESL students tend to rely heavily on dictionaries and translators when they are presented with reading material, so they often find themselves giving advice such as “You don’t have to understand every word to understand the reading, try not to look up every word in your dictionary.” Although students may reluctantly follow this advice in the classroom, most will continue to rely on dictionaries or translators when reading outside of class. This is because many L2 readers tend to draw heavily on bottom-up, or data driven reading strategies. They believe that successful reading comprehension hinges solely on their ability to understand the written text in front of them.