diff --git a/src/components/Practice/Mechanics3.jsx b/src/components/Practice/Mechanics3.jsx
index 59011c36..e0dbffb1 100644
--- a/src/components/Practice/Mechanics3.jsx
+++ b/src/components/Practice/Mechanics3.jsx
@@ -218,7 +218,7 @@ const Mechanics2 = ({
   };
 
   const [currrentProgress, setCurrrentProgress] = React.useState(0);
-  const progressBarWidth = isNaN(currrentProgress / duration)
+  const progressBarWidth = Number.isNaN(currrentProgress / duration)
     ? 0
     : currrentProgress / duration;
 
diff --git a/src/components/Practice/Mechanics6.jsx b/src/components/Practice/Mechanics6.jsx
index 850a8666..9b87bccb 100644
--- a/src/components/Practice/Mechanics6.jsx
+++ b/src/components/Practice/Mechanics6.jsx
@@ -144,8 +144,8 @@ const Mechanics2 = ({
       }
 
       // if (type === "audio") {
-      const isSoundCorrect = word === wordToCheck ? true : false;
-      var audio = new Audio(isSoundCorrect ? correctSound : wrongSound);
+      const isSoundCorrect = word === wordToCheck;
+      let audio = new Audio(isSoundCorrect ? correctSound : wrongSound);
       if (!isSoundCorrect) {
         setEnableNext(false);
       }
@@ -433,6 +433,7 @@ const Mechanics2 = ({
       >
         {words?.map((elem) => (
           <Box
+            key={elem}
             className={`${
               type === "audio" && selectedWord === elem
                 ? selectedWord === parentWords
diff --git a/src/utils/constants.js b/src/utils/constants.js
index 100a433d..635f6e67 100644
--- a/src/utils/constants.js
+++ b/src/utils/constants.js
@@ -3403,13 +3403,13 @@ export const levelGetContent = {
       title: "P5",
       criteria: "sentence",
       template: "simple",
-      mechanism: { id: "", name: "fillInTheBlank" },
+      mechanism: { id: "mechanic_1", name: "fillInTheBlank" },
     },
     {
       title: "P6",
       criteria: "sentence",
       template: "simple",
-      mechanism: { id: "", name: "fillInTheBlank" },
+      mechanism: { id: "mechanic_1", name: "fillInTheBlank" },
     },
     { title: "P7", criteria: "sentence", template: "simple" },
     { title: "P8", criteria: "sentence", template: "simple" },
@@ -3442,7 +3442,7 @@ export const levelGetContent = {
       title: "P5",
       criteria: "sentence",
       template: "simple",
-      mechanism: { id: "", name: "fillInTheBlank" },
+      mechanism: { id: "mechanic_1", name: "fillInTheBlank" },
     },
     {
       title: "P6",