What I don't understand is whether I can put 'an inspiration' as
an object.”
This is an equative sentence, so it has no object;
an inspiration is a subject complement.
Yes, you can have two or more things 'equal' to one.
The use of
are is technically correct, but if you said
is instead of
are, hardly anyone would notice.
According to some, frequent heat waves and mild winters are a sign of global warming.
Greenhouse gas emissions and the polluted air that results from them are a problem.
Intelligence and persistence are the key to success.
CJ