灯关了，门也锁了，所以我到的时候大家肯定都已经走了。
The lights were off and the door was locked, so everyone had to be gone by the time I arrived.
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had英 /hæd/|美 /hæd/
to英 /tuː/|美 /tu/|英 /tə/|美 /tə/
Be英 /biː/|美 /bi/
解释
had to be 是 has to 的过去式，表示对过去情况的推断，基于锁门和关灯的证据得出必然结论。
The lights were off and the door was locked, so everyone had to be gone by the time I arrived.
had to be 是 has to 的过去式，表示对过去情况的推断，基于锁门和关灯的证据得出必然结论。