TEMA

var input = require('fs').readFileSync('/dev/stdin', 'utf8');
var lines = input.split('\n');

var numberOfTests = parseInt(lines.shift());
var count = 0;

while (count < numberOfTests) {
    var string1 = lines.shift();
    var string2 = lines.shift();
    console.log(combineStrings(string1, string2));
    count++;
}

function combineStrings(string1, string2) {
    var i = 0;
    var j = 0;
    var k = 0;

    string1 = string1.split('');
    string2 = string2.split('');

    var newString = new Array(string1.length + string2.length);

    while (i < newString.length) {
        if (j < string1.length) {
            newString[i] = string1[j];
            j++;
            i++;
        }
        if (k < string2.length) {
            newString[i] = string2[k];
            k++;
            i++;
        }
    }

    return newString.join('');
}