#include <bits/stdc++.h>
using namespace std;
const int inf = 0x3f3f3f3f, mod = 1000000007;
const long long INF = 0x3f3f3f3f3f3f3f3fLL;
const double pi = acosl(-1.), eps = 1e-9;
inline int power(int a, int b, int m = mod, int ans = 1) {
  for (; b; b >>= 1, a = 1LL * a * a % m)
    if (b & 1) ans = 1LL * ans * a % m;
  return ans;
}
int que(vector<int> a, vector<int> b) {
  printf("%d %d ", a.size(), b.size());
  for (auto r : a) cout << r << ' ';
  for (auto r : b) cout << r << ' ';
  fflush(stdout);
  int ans;
  cin >> ans;
  return ans;
}
int main() {
  int T;
  cin >> T;
  while (T--) {
    int n;
    scanf("%d", &n);
    vector<int> a, b;
    a.push_back(1);
    for (int i = 2; i <= n; i++) b.push_back(i);
    int t = que(a, b);
    int st = 1, ed = n;
    while (st + 1 < ed) {
      int md = st + ed >> 1;
      b.clear();
      for (int i = 2; i <= md; i++) b.push_back(i);
      if (que(a, b) == t)
        ed = md;
      else
        st = md;
    }
    a.clear();
    b.clear();
    a.push_back(ed);
    for (int i = 1; i <= n; i++)
      if (ed != i) b.push_back(i);
    t = que(a, b);
    printf("-1 %d\n", t);
    fflush(stdout);
  }
  return 0;
}
