#include <bits/stdc++.h>
using namespace std;
const long long inf = 1e18;
const long long maxu = 200005;
signed main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  long long i, j, k = 0, n, t = 1, m, l = 0;
  cin >> t;
  while (t--) {
    cin >> n;
    if (n == 2) {
      cout << 1 << " " << 1 << " " << 1 << " " << 2 << endl;
      cin >> l;
      cout << -1 << " " << l << endl;
      continue;
    }
    long long lo = 2;
    long long hi = n;
    cout << 1 << " " << hi - lo + 1 << " " << 1 << " ";
    for (i = lo; i <= hi; i++) cout << i << " ";
    cout << endl;
    cin >> l;
    long long node = n;
    long long ans = l;
    while (lo <= hi) {
      m = (lo + hi) / 2;
      cout << 1 << " " << m - lo + 1 << " " << 1 << " ";
      for (i = lo; i <= m; i++) cout << i << " ";
      cout << endl;
      cin >> l;
      if (l == ans) {
        node = m;
        hi = m - 1;
      } else
        lo = m + 1;
    }
    cout << 1 << " " << n - 1 << " " << node << " ";
    for (i = 1; i <= n; i++) {
      if (i == node) continue;
      cout << i << " ";
    }
    cout << endl;
    cin >> l;
    cout << -1 << " " << l << endl;
  }
  return 0;
}
