#include <bits/stdc++.h>
using namespace std;
int main() {
  long long int i;
  cin >> i;
  while (i--) {
    int k;
    vector<int> l;
    cin >> k;
    for (unsigned long long int i = 0; i < k; i++) {
      int p;
      cin >> p;
      l.push_back(p);
    }
    vector<int> count_odd;
    bool flag = false, odd = false;
    for (unsigned long long int i = 0; i < k; i++) {
      if (count_odd.size() == 2) {
        flag = true, odd = true;
        break;
      } else {
        if (l[i] % 2)
          count_odd.push_back(i);
        else {
          cout << 1 << "\n" << i + 1 << "\n";
          flag = true;
          break;
        }
      }
    }
    if (count_odd.size() == 2) {
      flag = true, odd = true;
    }
    if (flag && odd) {
      cout << count_odd.size() << "\n";
      for (unsigned long long int i = 0; i < count_odd.size(); i++)
        cout << count_odd[i] + 1 << " ";
      cout << "\n";
    }
    if (!flag) cout << -1 << "\n";
  }
  return 0;
}
