instruction: Is the next sentence syntactically and semantically acceptable?

That Sam didn't pick those packages up is possible which are to be mailed tomorrow.

response: unacceptable


instruction: Is the next sentence syntactically and semantically acceptable?

Mary believed his to have loved her.

response: unacceptable


instruction: Is the next sentence syntactically and semantically acceptable?

Louis was forgiven by Susan.

response: acceptable


instruction: Is the next sentence syntactically and semantically acceptable?

Who are you gawking at?

response:
acceptable