#include <bits/stdc++.h>
using namespace std;
int arr[10001];
int main() {
  int test;
  cin >> test;
  while (test--) {
    int n;
    cin >> n;
    vector<int> ans1, ans2;
    for (int i = 0; i < 2 * n; i++) cin >> arr[i];
    vector<pair<int, int> > vp;
    for (int i = 0; i < 2 * n; i++) {
      if (arr[i] % 2 == 0)
        ans2.push_back(i + 1);
      else
        ans1.push_back(i + 1);
    }
    for (int i = 1; i < ans2.size(); i += 2)
      vp.push_back({ans2[i], ans2[i - 1]});
    for (int i = 1; i < ans1.size(); i += 2)
      vp.push_back({ans1[i], ans1[i - 1]});
    for (int i = 0; i < n - 1; i++)
      cout << vp[i].first << " " << vp[i].second << "\n";
  }
}
