#include <bits/stdc++.h>
using namespace std;
vector<string> split_string(string);
long long fun(vector<long long> a, long long l, long long r, long long sum) {
  long long n = a.size(), ch = 0, ans = 0;
  if (r - l == 1) {
    if (a[l] == a[r]) return 1;
    return 0;
  }
  if (r <= l) return 0;
  for (long long i = l; i < (r + 1); ++i) {
    ch += a[i];
    if (ch > sum) return 0;
    if (ch == sum) {
      if (sum & 1) return 1;
      ans = max(fun(a, l, i, sum / 2), fun(a, i + 1, r, sum / 2)) + 1;
      break;
    }
  }
  return ans;
}
long long arraySplitting(vector<long long> a) {
  long long n = a.size(), sum = 0;
  for (long long i = 0; i < (n); ++i) sum += a[i];
  if (sum & 1)
    return 0;
  else
    return fun(a, 0, n - 1, sum / 2);
}
int main() {
  int t;
  cin >> t;
  while (t--) {
    long long n, a;
    cin >> n;
    vector<long long> even, odd;
    for (long long i = 0; i < (n); ++i) {
      cin >> a;
      if (a & 1)
        odd.push_back(i + 1);
      else {
        even.push_back(i + 1);
      }
    }
    if (even.size() > 0) {
      cout << "1" << '\n' << even[0] << '\n';
    } else {
      if (odd.size() < 2)
        cout << "-1" << '\n';
      else {
        cout << "2" << '\n' << odd[0] << " " << odd[1] << '\n';
      }
    }
  }
}
