#include <bits/stdc++.h>
using namespace std;
long long add[1234567], a, b, c[1234567], c1[1234][1234], d[1234567], e, i, j,
    n, k, x, y, l, r;
map<char, long long> m;
vector<string> v1[1234567], v, vma, vmi;
vector<long long>::iterator it;
string s1[1234567], s;
multiset<long long> ms;
set<pair<string, long long>> se;
queue<long long> q;
deque<long long> dq;
pair<long long, long long> p[123456];
priority_queue<pair<long long, long long>> pq;
char ch[1234][1234];
int main() {
  cin >> k;
  while (k--) {
    cin >> n;
    a = 0;
    for (int i = 1; i <= n; i++) cin >> c[i];
    for (int i = 1; i <= n; i++) {
      if (c[i] % 2 == 1) {
        a++;
      }
    }
    if (n == 1 && a == 1) {
      cout << -1 << "\n";
    } else {
      b = 0;
      for (int i = 1; i <= n; i++) {
        if (c[i] % 2 == 0) {
          cout << 1 << "\n" << i << "\n";
          b = 1;
          break;
        }
      }
      if (b == 1)
        continue;
      else {
        cout << 2 << "\n"
             << "1 2";
      }
      cout << "\n";
    }
  }
}
