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