#include <bits/stdc++.h>
using namespace std;
const long long INF = 1e18;
struct custom_hash {
  static uint64_t splitmix64(uint64_t x) {
    x += 0x9e3779b97f4a7c15;
    x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
    x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
    return x ^ (x >> 31);
  }
  size_t operator()(uint64_t x) const {
    static const uint64_t FIXED_RANDOM =
        chrono::steady_clock::now().time_since_epoch().count();
    return splitmix64(x + FIXED_RANDOM);
  }
};
template <typename T>
istream& operator>>(istream& is, vector<T>& v) {
  for (auto& i : v) is >> i;
  return is;
}
template <typename T>
ostream& operator<<(ostream& os, vector<T>& v) {
  for (auto& i : v) os << i << ' ';
  return os;
}
long long mystoi(string str) {
  stringstream ss(str);
  long long ans = 0;
  ss >> ans;
  return ans;
}
long long exp(long long x, long long ex) {
  long long ans = 1ll;
  while (ex > 0) {
    if (ex & 1ll) ans = (ans * x);
    ex >>= 1ll;
    x = (x * x);
  }
  return ans;
}
bool sort_cond(const pair<long long, long long>& a,
               const pair<long long, long long>& b) {
  if (a.first == b.first) return a.second < b.second;
  return a.first < b.first;
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  long long t = 1;
  cin >> t;
  long long lo;
  while (t--) {
    long long n;
    cin >> n;
    vector<long long> a(2 * n);
    cin >> a;
    vector<long long> o, e;
    for (long long i = (0); i < (long long)(2 * n); i++) {
      if (a[i] % 2)
        o.push_back(i + 1);
      else
        e.push_back(i + 1);
    }
    long long cnt = 0;
    if (o.size() % 2) o.pop_back();
    if (e.size() % 2) e.pop_back();
    if (o.size() > e.size()) {
      for (long long i = (0); i < (long long)(o.size()); i++) {
        if (cnt == n - 1) break;
        cout << o[i] << " " << o[i + 1] << endl;
        cnt++;
        i++;
      }
      for (long long i = (0); i < (long long)(e.size()); i++) {
        if (cnt == n - 1) break;
        cout << e[i] << " " << e[i + 1] << endl;
        cnt++;
        i++;
      }
    } else {
      for (long long i = (0); i < (long long)(e.size()); i++) {
        if (cnt == n - 1) break;
        cout << e[i] << " " << e[i + 1] << endl;
        cnt++;
        i++;
      }
      for (long long i = (0); i < (long long)(o.size()); i++) {
        if (cnt == n - 1) break;
        cout << o[i] << " " << o[i + 1] << endl;
        cnt++;
        i++;
      }
    }
  }
}
