Complete the spy director's final warning to the rather clumsy Agent 007.5.

_____ by the evil Dr. Chaos, press the red button on your explosive bowtie immediately.

The correct answer is Should you be cornered.

This sentence is a variation of the first conditional, pairing an "if" clause with an imperative command ("press the red button").

When we want to make a future condition sound slightly less likely, we can use "should." By dropping if and inverting the subject and auxiliary verb, "If you should be cornered" becomes "Should you be cornered."

"Had you been cornered" is third conditional (past), and "Were you be" is grammatically invalid.