Select the best words for the blanks in the following sentence.
My new earrings, _________ are golden, are in a small box _________ Sylvia gave me.

“That” is used to introduce essential clauses. An essential clause is needed to make the sentence clear. Do not use commas to introduce an essential clause.
Example: My bike that has a flat tire is in the shed.
The example above infers that the speaker may have multiple bikes, so we have to specify that the bike that has the flat tire is the one that we are discussing.
“Which” is used to introduce non-essential clauses. A non-essential clause adds information to the sentence but is not necessary to make the meaning of the sentence clear. Use commas to set off non-essential clauses.
Example: My bike, which has a flat tire, is in the shed.
This example infers that the speaker only has one bike so we know the bike they are speaking of, but adding that the bike has a flat tire makes the sentence more descriptive and interesting.
If the blank comes after a comma, choose “which.” If the blank does not come after a comma, choose “that.”