$args=array(
'id_form' => 'commentform',
'id_submit' => 'submit',
'title_reply' => __( 'Leave a Reply' ),
'title_reply_to' => __( 'Leave a Reply to %s' ),
'cancel_reply_link' => __( 'Cancel Reply' ),
'label_submit' => __( 'Post Comment' ),
//display more comment fields with some defaults fields in which.
'fields'=>$fields,
//Text or HTML to be displayed after the set of comment fields (and before the submit button)
'comment_notes_after'=>'',
//Text or HTML to be displayed before the set of comment form fields if the user is not logged in.
'comment_notes_before'=>'',
//The textarea and the label of comment body. Sửa nội dung theo ý bạn.
'comment_field'=>''
);
//this tag output complete comment form
comment_form($args);