I am writing to you about the talk I agreed to give at the local library in two weeks' time这句话中为什么加about,还有week'是什么用法

I am writing to you about the talk I agreed to give at the local library in two weeks' time这句话中为什么加about,还有week'是什么用法
I am writing to you about the talk I agreed to give at the local library in two weeks' time
这句话中为什么加about,还有week'是什么用法

I am writing to you about the talk I agreed to give at the local library in two weeks' time这句话中为什么加about,还有week'是什么用法
1.write to sb about sth 写信给某人谈及某事
2.two weeks' 是表时间的词的‘s 属格形式作定语,修饰time
再如：today's newspaper
two hours' walk

about 在这就是“关于”啊，weeks' 是名词所有格的形式啊，意思就是“我写信给你，是关于我答应的在两星期后在图书馆作报告的事的。”