I have know idea what did I do wrong?

Tell us what’s happening:
I don’t know what I did wrong

Your code so far

// Only change code below this line

var myStr = "This is the first sentence .";
myStr += "This is the second sentence .";

Your browser information:

User Agent is: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/81.0.4044.138 Safari/537.36.

Challenge: Concatenating Strings with the Plus Equals Operator

Link to the challenge:

Try console.log()ing the result. You have some spacing issues.

You put the periods after a space from the last word, rather than the period after the last word followed by a space. Just a simple semantics thing with how the program processes things.