Which one sounds better?
1) What we need is books.
2) What we need are books.
I suspect that the second one is better. Is the first one acceptable?
***** NOT A TEACHER *****
1. IF I understand my books correctly, the first sentence is the grammatically correct one:
a. What ( = the thing that we need) is books.
Mona: We need something.
Tom: What thing?
Mona: That thing is books.
2. Nevertheless, I think that many native speakers (including some "good" writers) would feel that your second
sentence sounds more "natural."
3. As another member has just said, if this were on a test, probably No. 1 would please many teachers.