#include <bits/stdc++.h>
using namespace std;
void ask_question(int i, int j, int a, vector<int> &q) {
  cout << "1 " << (j - i) << " " << a << " ";
  for (int k = i; k < j; k++) cout << q[k] << " ";
  cout << endl;
}
int main() {
  int tc;
  cin >> tc;
  while (tc--) {
    int n;
    cin >> n;
    vector<int> q;
    for (int i = 2; i < n + 1; i++) q.push_back(i);
    int l = 0, r = n - 1;
    ask_question(l, r, 1, q);
    int ans, mx;
    cin >> mx;
    int cnt = 0;
    while (cnt < 7 && r - l > 1) {
      int mid = (l + r) >> 1;
      ask_question(l, mid, 1, q);
      cin >> ans;
      if (ans == mx) {
        mx = ans;
        r = mid;
      } else
        l = mid;
      cnt++;
    }
    cout << "1 " << (n - 1) << " " << q[l] << " ";
    for (int i = 1; i < n + 1; i++) {
      if (i == q[l]) continue;
      cout << i << " ";
    }
    cout << endl;
    cin >> ans;
    cout << "-1 " << ans << endl;
  }
  return 0;
}
