Sometimes I get confused by the usage of "what" as a pronoun. Specifically, I am not sure if "what" stands for "the thing that" or for "the things that" or for both.
For example, which of the following are acceptable:
"What makes her laugh is dirty jokes."
"What makes her laugh are dirty jokes."
"What make her laugh is dirty jokes."
"What make her laugh are dirty jokes."
And some corresponding examples which might or might not make a difference to the answer:
"What makes her laugh is dirty jokes and wet puppies."
"What makes her laugh are dirty jokes and wet puppies."
"What make her laugh is dirty jokes and wet puppies."
"What make her laugh are dirty jokes and wet puppies."
Best Answer
I think it becomes more clear whether it's are or is when you phrase it as a question.
This is the same question as
You would use 'are' if there are multiple things that make her laugh. Here's another example.
In other words, it's not whether the thing that makes her laugh is singular or plural, it's how many different things are there that make her laugh.