#include <iostream>

using namespace std;

int main(void)
{
    int t;
    cin >> t;
    while (t--)
    {
        int a, b;
        cin >> a >> b;
        string s;
        cin >> s;
        //number of zeroes in the string
        int count_z = 0;
        //number of ones in the string
        int count_o = 0;
        //number of ?(s) in the string
        int count_q = 0;
        int n = a + b;
        bool p = true;
        for (int i = 0; i < n; i++)
        {
            if (s[i] == '0')
            {
                count_z++;
            }
            if (s[i] == '1')
            {
                count_o++;
            }
            if (s[i] == '?')
            {
                count_q++;
            }
        }
        for (int i = 0; i < n; i++)
        {
            // get the element at n - i - 1 position
            int trans;
            if ((n - i - 1) >= 0)
            {
                trans = n - i - 1;
            }
            else
            {
                trans = 0;
            }
            if (s[i] == '?' && s[ n - i- 1] == '?')
            {
                if (i != trans)
                {
                    if (count_o < b)
                    {
                        s[i] = '1';
                        s[trans] = '1';
                        count_o = count_o + 2;
                        count_q = count_q - 2;
                    }
                    else if (count_z < a)
                    {
                        s[i] = '0';
                        s[trans] = '0';
                        count_z = count_z + 2;
                        count_q = count_q - 2;
                    }
                }
                else
                {
                    if (count_o < b)
                    {
                        s[i] = '1';
                        count_o++;
                        count_q--;
                    }
                    else if (count_z < a)
                    {
                        s[i] = '0';
                        count_z++;
                        count_q--;
                    }
                }
            }
            else if (s[i] == '?' && s[trans] != '?')
            {
                s[i] = s[trans];
                if (s[trans] == '0')
                {
                    count_z++;
                }
                else
                {
                    count_o++;
                }
                count_q--;
            }
            else if (s[i] != '?' && s[trans] == '?')
            {
                s[trans] = s[i];
                if (s[i] == '0')
                {
                    count_z++;
                }
                else
                {
                    count_o++;
                }
                count_q--;
            }
            else if (s[i] != '?' && s[trans] != '?' && s[i] != s[trans])
            {
                cout << -1;
                p = false;
                break;
            }
        }
        if (!(count_z == a && count_o == b))
        {
            cout << -1;
        }
        if (count_z == a && count_o == b && p)
        {
            for (int i = 0; i < n; i++)
            {
                cout << s[i];
            }
        }
        cout << endl;
    }
}