#include <bits/stdc++.h>
using namespace std;
const int mod = 1e9 + 7;
const int INF = 0x3f3f3f3f;
const int maxn = 3e6 + 15;
int main() {
  int t;
  scanf("%d", &t);
  for (int k = 1; t >= k; k++) {
    int n;
    scanf("%d", &n);
    int l = 2, r = n;
    printf("1 %d", n - 1);
    for (int i = 1; n >= i; i++) {
      printf(" %d", i);
    }
    printf("\n");
    fflush(stdout);
    int mx;
    scanf("%d", &mx);
    while (l <= r) {
      int mid = (l + r) >> 1;
      printf("1 %d 1", mid - l + 1);
      for (int i = l; mid >= i; i++) {
        printf(" %d", i);
      }
      printf("\n");
      fflush(stdout);
      int now;
      scanf("%d", &now);
      if (now == mx)
        r = mid - 1;
      else
        l = mid + 1;
    }
    printf("1 %d %d", n - 1, l);
    for (int i = 1; n >= i; i++) {
      if (i != l) printf(" %d", i);
    }
    printf("\n");
    fflush(stdout);
    scanf("%d", &mx);
    printf("-1 %d\n", mx);
    fflush(stdout);
  }
  return 0;
}
