text: // #pragma GCC optimize("Ofast,unroll-loops")
  // #pragma GCC target("avx,avx2,fma")
  
  #include <bits/stdc++.h>
  using namespace std;
  
  #define ll long long
  #define ull unsigned long long
  #define dd double
  #define ld long double
  #define sl(n) scanf("%lld", &n)
  #define si(n) scanf("%d", &n)
  #define sd(n) scanf("%lf", &n)
  #define pll pair <ll, ll>
  #define pii pair <int, int>
  #define mp make_pair
  #define pb push_back
  #define all(v) v.begin(), v.end()
  #define inf (1LL << 62)
  #define loop(i, start, stop, inc) for(ll i = start; i <= stop; i += inc)
  #define for1(i, stop) for(ll i = 1; i <= stop; ++i)
  #define for0(i, stop) for(ll i = 0; i < stop; ++i)
  #define rep1(i, start) for(ll i = start; i >= 1; --i)
  #define rep0(i, start) for(ll i = (start-1); i >= 0; --i)
  #define ms(n, i) memset(n, i, sizeof(n))
  #define casep(n) printf("Case %lld:", ++n)
  #define pn printf("\n")
  #define pf printf
  #define EL '\n'
  #define fastio std::ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
  
  const ll sz = 1e3 + 10;
  ll ara[2*sz];
  vector <pll> ans;
  vector <ll> odd, ev;
  
  int main()
  {
      ll t;
      sl(t);
      while(t--) {
          ll n;
          sl(n);
  
          ll m = 2*n;
          for1(i, m) {
              sl(ara[i]);
  
              if(ara[i] & 1) odd.pb(i);
              else ev.pb(i);
          }
  
          while(ans.size() < n-1) {
              if(odd.size() >= 2) {
                  ll p1 = odd.back();
                  odd.pop_back();
  
                  ll p2 = odd.back();
                  odd.pop_back();
  
                  ans.pb(mp(p1, p2));
              }
              else {
                  ll p1 = ev.back();
                  ev.pop_back();
  
                  ll p2 = ev.back();
                  ev.pop_back();
  
                  ans.pb(mp(p1, p2));
              }
          }
  
          for(pll &p : ans)
              pf("%lld %lld\n", p.first, p.second);
  
          ans.clear(), odd.clear(), ev.clear();
      }
  
      return 0;
  }