def drop_columns(tabular, n):
    """drops first n items from each row and returns new tabular data

    >>> drop_columns([[1, 2, 3],
                      [21, 22, 23],
                      [31, 32, 33]],
                     1)
    [[2, 3], [22, 23], [32, 33]]
    """
    return [row[n:] for row in tabular]