Word Blanks can anyone explain it

Tell us what’s happening:

Your code so far


function wordBlanks(dog, big, ran, quickly) {
  // Your code below this line
  var result = "";
result += "That day we saw a"  +"dog"+  "it was really"  +"big"+  " , so we"  +"ran"+  "from there"  +"quickly.";
  // Your code above this line
  return result;
}

// Change the words here to test your function
//wordBlanks("dog", "big", "ran", "quickly");

Your browser information:

User Agent is: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/69.0.3497.100 Safari/537.36.

Link to the challenge:
https://learn.freecodecamp.org/javascript-algorithms-and-data-structures/basic-javascript/word-blanks