17. The director, as well as the choir members, has agreed to appear on television.
You are correct! The sentence is grammatically correct.
"Director" is the subject of the sentence and is singular. So the verb, "has agreed" (singular) is correct.
"As well as" is not a conjunction. "As well as the choir members" is essentially the same as "just like the choir members" - the sentence would
then read "Just like the choir members, the director has agreed to appear on television."
If a conjunction ("and") had been used and if the sentence read "The director and the choir members...," the verb would have to be plural ("have agreed"). The sentence would read: "The director and
the choir members have agreed to appear on television."
You are correct! The sentence is grammatically correct.