[QUOTE=birgit33;811150]"Keep your car doors locked, and your windows rolled up at all times."
NOT A TEACHER
(1) I most respectfully and humbly suggest that this sentence is a simple sentence.
(2) Let's simplify it for easier analysis:
(You) + keep + doors (locked) and windows (rolled up).
(3) You = subject.
(4) keep = verb.
(5) doors = object ("locked" is objective complement of "doors," describing the state of the door).
(6) windows = object ("rolled up" is objective complement of "windows," describing the ...).
(7) doors and windows = compounded object.
(8) I respectfully suggest that the comma after "locked" should not be there. It has
given the false impression of the sentence being a compound one, which -- IMHO -- it
definitely is not.
(9) It is similar to any other command with a compounded object:
Eat up all your broccoli and tomatoes!
(10) It could be analyzed as a compound sentence only if the speaker's intention was
You keep your doors locked, and you keep your windows rolled up at all times!
Of course, I do not know the intentions of the speaker, but I humbly suggest that the
speaker was saying:
Keep doors locked and windows rolled up!
(Of course, if a teacher shows my analysis to be flawed, I shall immediately delete this post. We non-teachers are warned against misleading readers.)