in a year's time和 in a year有什么区别

in a year's time是在一年的时间里
而 in a year是在一年
例句：
In a year's time we will all be laughing about it.
一年以后我们都会对此一笑置之。
It's risky to assume that we know what voters will be thinking in a year's time.
自以为我们了解投票人在一年后的想法是很危险的行为。
They will swap posts in a year's time, according to new party rules which rotate the leadership.
根据轮流担任领导的新政党章程，他们在一年后会轮换职位。