When English speakers talk about time and place, there are three little words that often come up: in, on, and at. These common words are prepositions that show a relationship between two words in a sentence.
Some prepositions are rather easy for English learners to understand: behind, over, under, next to, etc...
一些介词对英语学习者来说很容易理解，像behind, over, under ,next to等等。
But these little two-letter prepositions seem to create confusion. Here are a few rules to help you understand when to use in, on, and at in a sentence.
For describing time and place, the prepositions in, on, and at go from general to specific.
Prepositions and Time
Let's start by looking at how we talk about time. English speakers use in to refer to a general, longer period of time, such as months, years, decades, or centuries. For example, we say "in April," "in 2015" or "in the 21st century."
Moving to shorter, more specific periods of time, we use on to talk about particular days, dates, and holidays . You may hear, "I went to work on Monday," or "Let's have a picnic on Memorial Day."
For the most specific times, and for holidays without the word "day," we use at. That means you will hear, "Meet me at midnight," or "The flowers are in bloom at Easter time."
Prepositions and Place
When English speakers refer to a place, we use in for the largest or most general places. You can say that "VOA is located in Washington, D.C." And "for the best food, try the restaurants in Chinatown."
For more specific places, like certain streets, we use the preposition on. You may know that President Obama lives on Pennsylvania Avenue in Washington, D.C.
Finally, we get to the most specific places. For exact addresses or intersections, we use the preposition at. If I invited you to visit us here at VOA, I would say, "Come to my office at 330 Independence Avenue." To be exact, it's at the corner of Independence and 3rd Street."
In English, though, there is always an ‘exception to the rule.' When talking about transportation, things get a little hard to understand. We use on for public vehicles like buses or trains, but also for smaller ones like a bicycle. "I rode there on my bicycle." However, you ride in a car.
然而在英语中总会有些例外。当我们谈到交通时，情况就有点难以理解。我们在谈到公交或火车等公共车辆用on，但是谈到较小的交通工具像自行车时也用on。“我骑自行车去那里的。”然而，乘坐小汽车我们说ride in a car。
Still, it helps to know that English prepositions do have some rules.
Following the "general to specific" rule should help you most of the time.
I'm Jill Robbins.