#include <bits/stdc++.h>
using namespace std;
int s[1000000] = {0};
int ss[1000000] = {0};
int main() {
  int t, n, m, i, j, a = 0, b = 0, a1 = 0;
  cin >> t;
  while (t--) {
    cin >> n;
    for (i = 1; i <= n; i++) {
      cin >> s[i];
      if (s[i] % 2 == 1 && a != 0 && a1 == 0) a1 = i;
      if (s[i] % 2 == 1 && a == 0) a = i;
      if (s[i] % 2 == 0 && b == 0) b = i;
    }
    if (n == 1 && b == 0)
      printf("-1\n");
    else {
      if (b != 0) {
        printf("1\n%d\n", b);
      } else
        printf("2\n%d %d\n", a, a1);
    }
    a = 0, b = 0, a1 = 0;
  }
  return 0;
}
