Do you remember the sections on how to declare variables, with the key words var, let and const? Look them up and see which one looks like it would be for a read only variable.
read-only var is const, it’s read-only because when you assign its value, it can’t be changed, and it can be read only
When you use var for this challenge, notice that failed test say to use const
when you are using "This is the start." + "This is the end.", notices that what you are providing This is the start.This is the end., isn’t what is required This is the start. This is the end., so the first test fall, as well.
So, don’t use var myStr and only change the value of const myStr while accounting for spaces