To insert the missing commas, follow these steps:
1. Identify the different clauses or phrases within each sentence.
2. Determine the appropriate places to separate these clauses or phrases using commas.
3. Insert the commas in the correct positions.
Here are the sentences with the missing commas inserted:
1. I heard very clearly when the chair next to me moved, but my eyes stayed carefully focused on the pattern I was drawing.
Explanation: The comma is inserted after "moved" to separate the independent clauses "I heard very clearly when the chair next to me moved" and "my eyes stayed carefully focused on the pattern I was drawing."
2. In a lot of ways, living with Charlie was like having my own place, and I found myself reveling in the aloneness instead of being lonely.
Explanation: Two independent clauses are separated by a coordinating conjunction ("and"). Therefore, a comma is needed before the coordinating conjunction "and" to separate the clauses.
3. I could hear how crazy it sounded, and I couldn't continue.
Explanation: Again, two independent clauses are connected by a coordinating conjunction ("and"), so a comma is needed before the conjunction "and" to properly separate the clauses.