When you acclimatize or are acclimatized to a new situation, place, or climate, you become used to it.
①They have been travelling for two days and will need some time to acclimatise.
②I hadn't had any time to acclimatize myself.
《经济学人》一篇关于城市和乡村老鼠的文章 Country bumpkins and city slickers 也出现了这个表达：
[scode type="blue"]gain on
If you gain on someone or something that is moving in front of you, you gradually get closer to them.
①In some places he was quicker and at others I'd gain on him.
②The Mercedes began to gain on the van.
They are gaining on us.
They are gaining on us! We need to go faster!