This is the hypothetical/imaginary should , which has IMO for "translations" here here, (which I'm providing here just so you understand, because the original version is one of the best): If he were to fail the exam, I would be very said. ): If by any chance he will not pass the exam, I will be very said. The inversion should he makes this imaginary.
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.