关联模型只能取到1个值

场景：取出一篇文章对应的所有tags，已经关联好了多对多模型
`class Article extends Model
{

public  $timestamps=false;
protected $table='article';
protected $primaryKey='art_id';
protected $guarded=['art_id'];
protected $events=[
    'created'=>ArticlePublished::class,
];
public function tags() {
    return $this->belongsToMany(Tag::class,'article_tag','tag_id','article_id');

}

}`

然后在控制器中
`$art=Article::find($art_id);

    //tags
    $tags=$art->tags()->select('id','text')->get();
    dd($art->tags);`

结果只取到了1个tag
`Collection {#572 ▼
#items: array:1 [▼

0 => Tag {#573 ▼
  #guarded: array:1 [▶]
  #primaryKey: "id"
  #table: "tags"
  #connection: "mysql"
  #keyType: "int"
  +incrementing: true
  #with: []
  #withCount: []
  #perPage: 15
  +exists: true
  +wasRecentlyCreated: false
  #attributes: array:6 [▶]
  #original: array:8 [▶]
  #casts: []
  #dates: []
  #dateFormat: null
  #appends: []
  #events: []
  #observables: []
  #relations: array:1 [▶]
  #touches: []
  +timestamps: true
  #hidden: []
  #visible: []
  #fillable: []
}

]
}`

昨天试了好久都只能取到一个啊。。问了好多人也不能解决这个奇怪的问题