Backstepping
n. 逐步退焊法\\nv. 往后退（backstep的ing形式）
🗣️ 情景例句
It's too noisy for some older people like Nat.
它对于像Nat这样的老人来说太吵了。
Not only did he make a promise, but he also kept it.
他不仅许下诺言，而且遵守了。
In 1990?
1990年呢？