#include <bits/stdc++.h>
using namespace std;
constexpr int maxn = 2e5 + 5, inf = 0x3f3f3f3f;
int n, m, tt;
int a[maxn];
int main() {
  cin >> tt;
  while (tt--) {
    cin >> n;
    int a1 = 0, a2 = 0;
    int f1 = 0, f2 = 0;
    int x = 0;
    int g = 1;
    for (int i = 1; i <= n; i++) {
      cin >> a[i];
      if ((a[i] & 1) && g == 1)
        a1++, g ^= 1, f1 = i;
      else if ((a[i] & 1) && !g)
        a1++, g ^= 1, f2 = i;
      else
        a2++, x = i;
    }
    if (a2) {
      puts("1");
      printf("%d\n", x);
    } else if (a1 >= 2) {
      puts("2");
      printf("%d %d\n", f1, f2);
    } else
      puts("-1");
  }
  return 0;
}
