#include <bits/stdc++.h>
using namespace std;
int i, n, t, a[105];
int main() {
  for (cin >> t; t--;) {
    cin >> n;
    for (i = 0; i++ < n;) cin >> a[i];
    if (a[1] & 1) {
      if (n < 2)
        cout << -1 << endl;
      else if (a[2] & 1)
        cout << 2 << endl << 1 << ' ' << 2 << endl;
      else
        cout << 1 << endl << 2 << endl;
    } else
      cout << 1 << endl << 1 << endl;
  }
}
