instruction: Is the next sentence syntactically and semantically acceptable?

I separated the milk of the cream.

response: unacceptable

instruction: Is the next sentence syntactically and semantically acceptable?

Stephen is believed to be easy to annoy Ben.

response: unacceptable

instruction: Is the next sentence syntactically and semantically acceptable?

Ellen warned for Helen to come.

response: unacceptable

instruction: Is the next sentence syntactically and semantically acceptable?

Ellen said something to Helen.

response:
acceptable