Car NOS script not working

i am working on a car game but i am facing some scripting problems
i am pretty new to unity so all the help is welcome
using UnityEngine;
using System.Collections;

public class NOS : MonoBehaviour {

var isReady : boolean = true;
var vehicle : GameObject;
var waitTime : float;
// Update is called once per frame
void Update () {

	if(Input.GetKeyDown("left shift") && isReady){
     Nitrous();
 }

}
function Nitrous(){
	isReady = false;
	vehicle.rigidbody.AddForce (transform.forward * 1000, ForceMode.Acceleration);
	yield WaitForSeconds (waitTime);
	isReady = true;
}

}

Errors

First of all, I see you’re using C#, but your variables are in JavaScript format. (Var a : b). Change

var isReady : boolean = true;
 var vehicle : GameObject;
 var waitTime : float;

To this

public bool isReady = true;
public GameObject vehicle;
public float waitTime;

Also change

yield WaitForSeconds  (waitTime);

To

yield return new WaitForSeconds  (waitTime);

It’s really just that simple

Converted the script completely to C# and changed the Nitrous function to a IEnumerator (Coroutine) so you can use WaitForSeconds. This should be completely usable.

using UnityEngine;
using System.Collections;

public class NOS : MonoBehaviour {
	bool isReady = true;
	GameObject vehicle;
	float waitTime;
	// Update is called once per frame
	void Update () {

		if (Input.GetKeyDown(KeyCode.LeftShift) && isReady) {
			StartCoroutine(Nitrous());
		}
	}
	
	IEnumerator Nitrous() {
		isReady = false;
		vehicle.GetComponent<Rigidbody>().AddForce (transform.forward * 1000, ForceMode.Acceleration);
		yield return new WaitForSeconds(waitTime);
		isReady = true;
		yield return null;
	}
}