I got to do something=I've got to do something=I have to do something
前者在口语中更地道,更口语化。请看：
But you can’t leave with an opening door.
I got to buy a new lock. Plus, the superintendent won’t let any stranger in.
但你不能在开门的情况下离开。
我必须买一把新锁。另外，主管不想让任何陌生人进来。
As soon as we arrived, we got to work.
我们一到就必须开始工作。中考真题- 2019 长沙
We got to work on putting the book together.
我们得努力编成这本书。《柯林斯高阶英汉双解学习词典》
I got to run, my books are due in the library.
我得走了，我有图书馆的书要交了。
They got to tell you something.
他们总得告诉你点什么。
We’ll do what we got to do.
我们要去做我们该做的事。赵振才《英语常见问题解答大词典》增订版第五版P572.
I got to spend my second term at Yale as a proper law student with the heaviest class load of any stay there.比尔克林顿《我的生活》
我必须作为耶鲁大学法学专业的正式学生参加第二个学期的学习，这个学期是我在那里学习负担最重的一段时间。