#include <bits/stdc++.h>
using namespace std;
int main() {
  int t;
  cin >> t;
  while (t--) {
    int n, s = 0, f = 0, x, f1 = 0, freq;
    cin >> n;
    int a[n];
    for (int i = 0; i < n; i++) {
      cin >> a[i];
      if (a[i] % 2 == 0) {
        x = i;
        f = 1;
      }
      s += a[i];
      if (s % 2 == 0) {
        f1 = 1;
        freq = i;
      }
    }
    if (f == 1) {
      cout << 1 << endl << x + 1 << endl;
      continue;
    }
    if (f1 == 1) {
      cout << freq + 1 << endl;
      for (int i = 0; i < freq + 1; i++) cout << i + 1 << " ";
      cout << endl;
      continue;
    }
    if (s % 2 == 0) {
      cout << n << endl;
      for (int i = 0; i < n; i++) cout << i + 1 << " ";
    } else
      cout << -1;
    cout << endl;
  }
}
