问“未定义或导入预定义类型System.Void”在VisualStudio2017中编译统一2D c#脚本时出错

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using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class MyPlayerMovement : MonoBehaviour
{
    // Start is called before the first frame update
    void Start()
    {

    }

    // Update is called once per frame
    void Update()
    {

    }
}

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class PlayerMovement : MonoBehaviour {

    public CharacterController2D controller;
    public Animator animator;

    public float runSpeed = 40f;

    float horizontalMove = 0f;
    bool jump = false;
    bool crouch = false;

    // Update is called once per frame
    void Update () {

        horizontalMove = Input.GetAxisRaw("Horizontal") * runSpeed;

        animator.SetFloat("Speed", Mathf.Abs(horizontalMove));

        if(horizontalMove == 0)
        {
            animator.SetBool("Jumping", false);
        }

        if (Input.GetButtonDown("Jump"))
        {
            jump = true;
            animator.SetBool("Jumping", true);
        }

        if (Input.GetButtonDown("Crouch"))
        {
            crouch = true;
            animator.SetBool("Crouching", true);
        } else if (Input.GetButtonUp("Crouch"))
        {
            crouch = false;
            animator.SetBool("Crouching", false);
        }

    }

    void FixedUpdate ()
    {
        // Move our character
        controller.Move(horizontalMove * Time.fixedDeltaTime, crouch, jump);
        jump = false;
    }
}