instruction: Is the next sentence syntactically and semantically acceptable?

I know a man who John is taller than is.
OPTIONS:
- unacceptable
- acceptable

response: unacceptable

instruction: Is the next sentence syntactically and semantically acceptable?

Margaret cut at the bread.
OPTIONS:
- unacceptable
- acceptable

response: acceptable

instruction: Is the next sentence syntactically and semantically acceptable?

David constructed a house from bricks.
OPTIONS:
- unacceptable
- acceptable

response: acceptable

instruction: Is the next sentence syntactically and semantically acceptable?

Bob proved that this set is recursive.
OPTIONS:
- unacceptable
- acceptable

response:
acceptable