Expressing verbs in past tense is incredibly easy in Mandarin Chinese.
Think about English for a second
I am -> I was
I go -> I want
I eat -> I ate
I want -> I wanted
In English we are able to add “ed” to the end of SOME verbs. But of course we have all those irregular verbs that don’t have that capability as shown above. Well Mandarin is very easy. They also have a sort of “ed” if you like. The difference is every single verb in their language can be made past tense by using it, without exception.
It isn’t “ed” of course, it is “le” (pinyin spelling)
Adding “le” to the end of ANY verb renders it past tense. Sometimes the “le” is said right after the verb, but also sometimes the “le” is put at the very end of the sentence. I am not quite sure if there is any hard and fast rule about that, but as you learn the language I am sure you will pick up the feel of when to put “le” at the end of the sentence or right after the verb.
I yesterday eat “le” lunch
I yesterday eat lunch “le”
Here both sentences have the exact same meaning i.e. “I ate lunch yesterday”. Regardless of where the “le” appears the meaning is the same.
Another way to denote past tense is to surround the action with “shi4” and “de”. For example :
I “shi4” yesterday eat lunch “de” = I ate lunch yesterday.
Further, Mandarin also use “guo4” (4th tone) to denote past tense. However “guo” is used to denote sentences like :
I have been to China
I have eaten fish before
I have played tennis
These are the sentences where “guo” would be used. In English this tense is called “Past Perfect”. But if you don’t like grammar just think of “guo” as something that has happened at least once in the past, most likely a long time ago.
A simple way I like to think of it is like this
Did you go to China ? (for this question you would use “le” because you are asking about something that happened in the recent past)
Have you ever been to China ? (for this question you would use “guo” because you are asking if someone has ever done something at least once in the past)
Here are more sentences where “guo” would be used :
Have you ever eaten fish ?
Have you ever seen this movie ?
I have played football before
I tried it once
I have used it
These sentences generally talk about something in the distant past. However it is possible that the things above happened recently, however we are conveying the idea that we have done it at least once in our life whether that be recently or a long time ago. If you want to convey simple past tense in Mandarin just use “le” or the “shi” “de” combination.
In actual fact, many meanings can be conveyed simply through context. If you are talking about yesterday the listener already knows you are talking about the past and therefore it isn’t really necessary to ensure every verb has a “le” after it or whatever. The same rule applies when talking about the future. Mandarin is a language of logic, it isn’t clouded with endless grammar rules and regulations. Just say the bare minimum required to get the meaning across without all the filler and you are fine.