让我们来看看他们给出的提示：
如果你一直猜同一个正确的字母，“remainingLetters”会一直递减
是的，这是真的。当guess与之前的猜测相同时，则以下if条件仍然为真，并且其代码块将执行：

if (word[j] === guess) {
            answerArray[j] = guess;
            remainingLetters--;
        }

我们不希望重复的猜测对remainingLetters倒计时有任何影响。应该保持不变。
...您可以添加另一个条件来检查answerArray中的值是否仍然是下划线。
这是一个很好的提示，因为第一次猜测时，我们用guess替换了下划线：

answerArray[j] = guess;

所以...如果再次进行同样的猜测，answerArray[j]处的字符将不再是下划线，而是猜测的字母。因此，在我们决定进入if块之前，首先检查answerArray[j]处的字符是什么是一个好主意。
这是否有助于找出你应该做什么？
如果没有，这里是作为一个扰流器的解决方案
if (word[j] == guess && answerArray[j] == "_") {

// Set a maximum number of tries
var maximumTries = 10;

// Create an array of words
var words = [
    "quail",
    "chicken",
    "kookaburra",
    "parrot"
];

// Pick a random word
var word = words[Math.floor(Math.random() * words.length)];

// Set up the answer array
var answerArray = [];
for (var i = 0; i < word.length; i++) {
    answerArray[i] = "_";
}
var remainingLetters = word.length;

// This will hold all the letters tried
var guessAll = "";

// The game loop
while (remainingLetters > 0 && guessAll.length < maximumTries) {
    // Show the player their progress
    alert(answerArray.join(" "));

    // Get a guess from the player
    var guess = prompt("Guess a letter, or click Cancel to stop playing.");
    if (guess === null) {
        // Exit the game loop
        break;
    } else if (guess.length !== 1 || !/[a-z]/i.test(guess)) {
        alert("Please enter a single alphabetic character.");
    } else {
        guess = guess.toLowerCase();
        if (guessAll.includes(guess)) {
            alert("You have already guessed that letter.");
        } else {
            guessAll += guess;
            var found = false;
            for (var j = 0; j < word.length; j++) {
                if (word[j] === guess) {
                    answerArray[j] = guess;
                    remainingLetters--;
                    found = true;
                }
            }
            if (!found) {
                alert("Wrong guess!");
            }
        }
    }
}

// Show the answer and congratulate the player
alert(answerArray.join(" "));
if (remainingLetters === 0) {
    alert("Congratulations! You guessed the word: " + word);
} else {
    alert("Game over! The word was: " + word);
}