A. He bought that much food because he must be hungry.
B. She has bloodshot eyes because she must have cried.
C. They must still be at work because the lights are off.
D. She must be rich because she keeps changing her mobile phones although it's always expensive.
E. The problem must be difficult because he has been working on it for two hours.
F. They must be Chinese because they are eating with chopsticks.
G. They must have liked the film because it was interesting.
H. Something must have happened because she didn't come to my party.
