How do i rewrite this. After cleaning all day, the apartment was as sterile as an operating room l

The right way to rewrite the sentence is the following one:

After I had spent all day cleaning the apartment, it was as sterile as an operating room.

Explanation:

We want to convey the idea of two things that happened at different times of a day, which means there was a chronological order in which those events took place. Therefore, we want to use two verb tenses:

Past Perfect Tense: for the event that happened first.

Simple Past Tense: for the event that happened some time after the first one.

Check it out:

Past Perfect (1st event) Simple Past (2nd Event)

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After I had spent all day cleaning the apartment, it was as sterile as an operating room.

The apartment was as sterile as an operating room after I spent all day cleaning it.