Anytime you give a Google Slides presentation for a student to look at during this time of asynchronous learning, how can you know if a student is viewing the lesson?
Well, you can make it in to an "Answer this question" type deal. In my case, that doesn't work because my state has said my seniors have passed and cannot be penalized or rewarded for work completed or no completed (really makes it worthwhile to keep producing lessons....). So a student may look at the lesson, but may not answer any questions or complete any activities.
If you are in a similar situation or you just want to know who is looking at your lesson, well, you may be in luck. Pull up your Slides and see if you have the crooked arrow at the top of your screen.
If you have that, then your IT guys have enabled some analytics. Click it and you get this screen:
This doesn't tell you how much time they spent on the presentation or what effort they are putting into it, but at least you get an idea of who is at least putting forth some effort.
Hope this helps!