#include <bits/stdc++.h>
using namespace std;
int main() {
  long long t;
  cin >> t;
  while (t--) {
    long long n, a, i, j, fl = 0, max = 0, fl1 = 0;
    vector<long long> v, v1, v2;
    cin >> n;
    for (i = 0; i < n; i++) {
      cin >> a;
      v.push_back(a);
    }
    for (i = 0; i < n; i++) {
      if (v[i] % 2 == 0) {
        fl = 1;
        cout << "1" << endl << i + 1 << endl;
        break;
      }
    }
    if (fl == 0) {
      for (i = 0; i < n; i++) {
        if (v[i] % 2 != 0) {
          v1.push_back(v[i]);
          v2.push_back(i + 1);
          max = accumulate(v1.begin(), v1.end(), 0);
          if (max % 2 == 0) {
            cout << v1.size() << endl;
            for (j = 0; j < v2.size(); j++) {
              fl1 = 1;
              cout << v2[j] << " ";
            }
            cout << endl;
            break;
          }
          if (fl == 1) {
            break;
          }
        }
      }
    }
    if (fl == 0 && fl1 == 0) {
      cout << "-1" << endl;
    }
  }
  return 0;
}
