#include <bits/stdc++.h>
using namespace std;
int main() {
  int t, n;
  cin >> t;
  while (t--) {
    cin >> n;
    int a[n], flag = 0, x;
    for (int i = 0; i < n; i++) cin >> a[i];
    for (int i = 0; i < n; i++) {
      if (a[i] % 2 == 0) {
        x = i + 1;
        flag = 1;
        break;
      }
    }
    if (n == 1 && flag == 0)
      cout << "-1" << endl;
    else if (flag == 1)
      cout << "1" << endl << x << endl;
    else
      cout << "2" << endl
           << "1"
           << " "
           << "2" << endl;
  }
  return 0;
}
