#include <bits/stdc++.h>
using namespace std;
int main() {
  int t;
  cin >> t;
  while (t--) {
    int i, j, n, first = -1;
    cin >> n;
    vector<int> v(n, 0);
    for (i = 0; i < n; i++) {
      cin >> v[i];
      if (v[i] % 2 == 0) first = i;
    }
    int sum = v[0];
    i = 1;
    while (i < n && sum % 2) {
      sum += v[i];
      i++;
    }
    if (sum % 2) {
      if (first != -1) {
        cout << 1 << endl;
        cout << first + 1 << endl;
      } else
        cout << -1 << endl;
    } else {
      cout << i << endl;
      for (j = 1; j <= i; j++) cout << j << " ";
      cout << endl;
    }
  }
}
