def enumerate(s, start=0):
    """Returns a list of lists, where the i-th list contains i+start and
    the i-th element of s.

    >>> enumerate([6, 1, 'a'])
    [[0, 6], [1, 1], [2, 'a']]
    >>> enumerate('five', 5)
    [[5, 'f'], [6, 'i'], [7, 'v'], [8, 'e']]
    """
    # BEGIN Question 0
    return zip(range(start, start + len(s)), s)
    # END Question 0