Your sentence is easily understood. However, I contend that before and after imply that the action was completed. I would change this sentence to say: The plane took off without the completion of the securty checks.
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.
Anonymoushi philip, thanks for your reply, however i don't think you've answered my question. My question is-- why is the past perfect used in the original sentence, when the action described by the past perfect actually occurred after the main verb rather than before it.Sorry my thoughts weren't more clear. I don't think the past perfect should have been us