CS0103 and CS0246 with "public Text text;"

So when I define anything in public, for reference (LevelManager, Text) it makes it red and gives me error CS0246 and CS0103 as errors. Also, when I connect it to my object, the public doesn't give me a place to drag the thing I want to onto it. I'm new to Unity, and I have gone through the Q.A., but I can't find anything. HELP!!! Code:

 using UnityEngine;
 using UnityEngine.UI;
 using System.Collections;
 
 public class LoseColliderScript : MonoBehaviour {
 
     public LevelManager levelManager;
 
     void OnTriggerEnter2D (Collider2D trigger) {
         levelManager.LoadLevel("Win");
     }
 }
 

The main thing is that when I comment out the "public" line, everything works.