i need help
i am making a program that conjugates spanish words
this is only the beginning part that determines what the last two letters is(those are important)
when i put only the "if" part it works fine
but when i puts the "else if" and "else" parts in it doesn't work

var pronoun = prompt("What is your pronoun(put yo, tu, el, etc.)");
var verb = prompt("What is your verb");
if (verb.length === 2) {
var last = verb.substring(0,2);
};
else if (verb.length === 3) {
var last = verb.substring(1,3);
};
else if (verb.length === 4) {
var last = verb.substring(2,4);
};
else if (verb.length === 5) {
var last = verb.substring(3,5);
};
else if (verb.length === 6) {
var last = verb.substring(4,6);
};
else if (verb.length === 7) {
var last = verb.substring(5,7);
};
else if (verb.length === 8) {
var last = verb.substring(6,8);
};
else if (verb.length === 9) {
var last = verb.substring(7,19);
};
else if (verb.length === 10) {
var last = verb.substring(8,10);
};
else if (verb.length === 11) {
var last = verb.substring(9,11);
};
else if (verb.length === 12) {
var last = verb.substring(10,12);
};
else if (verb.length === 13) {
var last = verb.substring(11,13);
};
else if (verb.length === 14) {
var last = verb.substring(12,14);
};
else (verb.length === 15) {
var last = verb.substring(13,15);
};
alert(last)