I was twenty years old and ready for anything.
我当时二十岁，什么都愿意去做。
Twenty guests are enough, I would have thought.
我觉得二十位客人就够了。
There were twenty or so people there.
那儿有差不多二十个人。
Pick a number from one to twenty.
从一至二十中挑选一个数。
He finally won his freedom after twenty years in jail.
他蹲了二十年监狱以后终于获得了自由。