This is the first time that I have felt really relaxed for months.

【答】legend 是位细心的网友，的确，for months 放在这个位置不正确。应该放在the first time之后。此外，for months 介词用得不恰当，应改为：in months。如：

This is the first time in months that I have felt really relaxed.这是我数月中第一次感到真正的放松。

This is the first time in many years she has been scolded by her parents. 这是许多年来第一次，她被父母骂了一顿。

It was the first time in his life that he had travelled first class. 这是他有生以来第一次坐头等车。

（注：我在解答那个问题时，重点解释时态问题，忽略了这个短语的位置不当和介词错误。）

我仔细揣摩了原句的含义，应该就是“数月来第一次感到真正的放松”。如果for months位置不变，显然是指have relaxed持续的时间。那么，完成时跟the first time就无关了。说明原题在设计上有误。

【说明】假如for months 修饰动词have relaxed，那么句子的意思就是这个样子：

I have felt really relaxed for months，and this is the first time (in my life).

这显然不是设计者的原意，因为for months 这个短语本身就用于现在完成时，所以，跟This is the first time 就没有关系，考查完成时也就没有什么意义了。