WP_Comments_List_Table::get_columns()

	public function get_columns() {
		global $post_id;

		$columns = array();

		if ( $this->checkbox )
			$columns['cb'] = '<input type="checkbox" />';

		$columns['author'] = __( 'Author' );
		$columns['comment'] = _x( 'Comment', 'column name' );

		if ( ! $post_id ) {
			/* translators: column name or table row header */
			$columns['response'] = __( 'In Response To' );
		}

		$columns['date'] = _x( 'Submitted On', 'column name' );

		return $columns;
	}