Unity 3D 控制物体前后左右均匀移动脚本

function Update () {
    if(Input.GetKey(KeyCode.W)){
        print("w");
        transform.Translate(Vector3.forward * Time.deltaTime * -20);
    }
    if(Input.GetKey(KeyCode.S)){
        print("s");
        transform.Translate(Vector3.forward * Time.deltaTime * 20);
    }
    if(Input.GetKey(KeyCode.A)){
        print("a");
        transform.Translate(Vector3.left * Time.deltaTime * -20);
    }
    if(Input.GetKey(KeyCode.D)){
        print("d");
        transform.Translate(Vector3.left * Time.deltaTime * 20);
    }

}