#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  int t;
  cin >> t;
  while (t--) {
    int n;
    cin >> n;
    int arr[n];
    vector<int> odd, even;
    for (int i = 0; i < n; i++) {
      cin >> arr[i];
      if (arr[i] % 2 == 0)
        even.push_back(i + 1);
      else
        odd.push_back(i + 1);
    }
    if (n == 1 && arr[0] % 2 != 0)
      cout << -1 << "\n";
    else {
      if (odd.size() >= 2) {
        cout << 2 << "\n";
        cout << odd[0] << " " << odd[1] << "\n";
      } else if (even.size() != 0) {
        cout << 1 << "\n";
        cout << even[0] << "\n";
      }
    }
  }
  return 0;
}
