if else doesn't work

[purrup]

this does not work
what is wrong with it
making a program that conjugates Spanish verbs

var pronoun = prompt("What is your pronoun(put yo, tu, el, etc.)");

var verb = prompt("What is your verb");

var last = verb.substring(verb.length-2)

var first = verb.substring(0,verb.length-2)

var type = verb.substring(verb.length-2,verb.length-1);

if (pronoun === yo && type === a) {
alert(first + "o");
};

else if (pronoun === yo && type === e) {
alert(first + "e");
};

else (pronoun === yo && type === i) {
alert(first + "o");
};