instruction: Is the next sentence syntactically and semantically acceptable?

I never met that man who somebody tried to kill.

response: acceptable

instruction: Is the next sentence syntactically and semantically acceptable?

We saw him beaten by the champion.

response: acceptable

instruction: Is the next sentence syntactically and semantically acceptable?

To please John is eager.

response: unacceptable

instruction: Is the next sentence syntactically and semantically acceptable?

I wondered who it was you saw.

response:
acceptable