#include <bits/stdc++.h>
using namespace std;
int main() {
  int t;
  cin >> t;
  while (t--) {
    int ans = 0, n = 0;
    cin >> n;
    for (int i = 1; i <= n; i++) {
      int x;
      cin >> x;
      if (x % 2 == 0) ans = i;
    }
    if (ans)
      cout << "1\n" << ans << "\n";
    else {
      if (n == 1)
        cout << "-1\n";
      else
        cout << "2\n1 2\n";
    }
  }
  return 0;
}
