def _stringify_time_unit(value: int, unit: str):
    """
    Returns a string to represent a value and time unit,
    ensuring that it uses the right plural form of the unit.

    >>> _stringify_time_unit(1, "seconds")
    "1 second"
    >>> _stringify_time_unit(24, "hours")
    "24 hours"
    >>> _stringify_time_unit(0, "minutes")
    "less than a minute"
    """

    if value == 1:
        return f"{value} {unit[:-1]}"
    elif value == 0:
        return f"less than a {unit[:-1]}"
    else:
        return f"{value} {unit}"