FirebaseArduino.h:20:18: fatal error: string: No such file or directory (Arduino)

Question

I'm developing a project using FirebaseArduino library (Realtime database) on my Arduino Uno WiFi Rev2. When I ran my code, I got a mistake as following:
#include FirebaseArduino.h
#include WiFiNINA.h

Error message: C:\Users\Documents\Arduino\libraries\firebase-arduino-USER\master\src/FirebaseArduino.h:20:18: fatal error: string: No such file or directory

//FirebaseArduino.h lines 17 - 23

#ifndef FIREBASE_ARDUINO_H
#define FIREBASE_ARDUINO_H

#include <string> // Error 

#include "Firebase.h"
#include "FirebaseObject.h"

// my code

#include <WiFiNINA.h>  
#include <FirebaseArduino.h>

#define WIFI_SSID "SSID"      
#define WIFI_PASSWORD "PWD"          
#define FIREBASE_HOST "****"  
#define FIREBASE_AUTH "****" 

void setup() {

 //conect wifi
  WiFi.begin(WIFI_SSID, WIFI_PASSWORD);

  while (WiFi.status() != WL_CONNECTED)  
  {
  Serial.print(".");
  }

  Serial.println("");
  Serial.println("WiFi connected");

  Firebase.begin(FIREBASE_HOST, FAREBASE_AUTH);  

}

String firebaseGet(String s)
{
  String x = Firebase.getString(s);
  yield();
  delay(100);
  return x;
  delay(100);
}

void loop() {
  String firebaseStatus = firebaseGet("****");
  if (firebaseStatus == "ON") 
  {
  //code to happen if the status is ON

  }
  else if (firebaseResult == "OFF") 
  {
  //code to happen if the status is OFF
  }
}

I found some possible problems:

1 - Arduino IDE version INCOMPATIBLE -- Tried to use 1.8.5, 1.6.12 and failed; 1.6.9 doesn't have INCOMPATIBLE problem. But it still cannot run.

2 - Should install old library of firebase -- still cannot run