Further to the comments already given, your program is a very naive implementation of a conjugation script. Of course, it will give the wrong answer for lots of more or less irregular verbs. So even when you correct all the syntax errors, it will still not run "correctly" in the sense that it will not give you the right answers.

And yet, no need to despair or re-invent the wheel when CPAN will provide you with such nice modules as Lingua::EN::Conjugate:

use Modern::Perl qw/2015/;
use Lingua::EN::Conjugate qw/conjugate/;

while ( my $verb = <DATA> ) {
    chomp $verb;
    for my $pronoun (qw/I you he we you they/) {
        say conjugate(
            verb               => $verb,
            pronoun            => $pronoun,
            allow_contractions => 1,
            tense              => 'present',
        );
    }
    say '---------------------';
}

__DATA__
walk
hear
be
have
go
try
sing
may
[download]

Output:

I walk
you walk
he walks
we walk
you walk
they walk
---------------------
I hear
you hear
he hears
we hear
you hear
they hear
---------------------
I'm
you're
he's
we're
you're
they're
---------------------
I've
you've
he's
we've
you've
they've
---------------------
I go
you go
he goes
we go
you go
they go
---------------------
I try
you try
he tries
we try
you try
they try
---------------------
I sing
you sing
he sings
we sing
you sing
they sing
---------------------
I may
you may
he may
we may
you may
they may
---------------------
[download]

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