Backfilling
[机] 回填
🗣️ 情景例句
I have a new puppy and he has an excellent temperament.
我有只新的小狗，它的脾气很好。
We must not lie down, and cry, God help us.
求神不如求己。
The question was, which one?
问题是，哪一种气体导致火灾呢？