[Grammar] He gave me the letter, which was in a blue envelope.

[rock-onn]

He gave me the letter, which was in a blue envelope.

Why is comma used in the sentence? Thanks for the support.

 

[GoesStation]

With the comma included, "which was in a blue envelope" is additional description of the letter. If you omit the comma, it tells us which letter he gave you: the one in the blue envelope, not the one in the red envelope.

Ask Why is a comma used.