使用visual studio code为unity添加脚本时，显示命名空间不能直接包含字段或方法等成员，这种要怎么解决？
using UnityEngine;
public class PlayerMovement : MonoBehaviour
{public Rigibody rb;
// Start is called before the first frame update
void Start()
{
rb.useGravity = false;
}
// Update is called once per frame
void Update()
{
}
}
