Question

—Did you look up the time of trains to Shanghai?
—Yes, the earliest train is _____ to leave at 5:30 am.

A．likely

B．about

C．possible

D．due

Answer 1

D

be due to do意为“应该…/预期的”；be about to do 不和时间状语连用；possible主语应为it；而likely与句意不合。