A perfectly natural question to ask when you learn that Chinese characters represent words is: how do you indicate something like past tense? For speakers of Western languages it is a natural question, because they know that verbs change their form when the speaker wants to indicate that something happened in the past. I am washing - yesterday I washed. So how do you indicate that when you write with Chinese characters?
Well, big surprise, the Chinese themselves don't actually use a past tense, so they don't have to write anything differently.² The sentence ‘yesterday I washed’ becomes 昨天我洗滌³ which states simply YESTERDAY I WASHING, and the only difference with ‘I am washing’ 我洗滌 (I WASHING) is that they leave out ‘yesterday’ (昨天). So, instead of a past tense they use adverbs of time and things like that. But that's not the whole story. First of all, while Chinese does not have a full blown past tense, it does have a way to indicate a completed action. For example, a sentence like ‘the train has arrived’ indicates not only past tense, but also a completed action, and that can be expressed by adding an extra word. 火車到達了 (TRAIN ARRIVING DONE).⁴ Also, the big difference between Chinese and most Western languages is not that it does not have a past tense, but that is does not conjugate (change the form of) its verbs to indicate things like that. The verbs stay the same, but they may add an extra word (like 了, for showing a completed action).
Then there is Japanese. It turns out that that language is written with Chinese Characters as well. And in fact, The Japanese conjugate their verbs all the time. So how do they do it? Well, they not only use Chinese Characters, but also a syllabary (a kind of alphabet) and simply write verb endings after the Chinese character. For the verb stem they use Chinese character(s), and for the verb ending they add extra letters.
For example, the Japanese verb kuru (to come; arrive) is written 来る, which consists of the Chinese character 来 followed by the letter る (that stands for ru) to indicate the verb ending. In the example sentence ‘the train has arrived’ (電車が来た densha ga kita) the verb kuru is conjugated to kita - which has a different verb ending. In written Japanese 来る → 来た. Since the verb endings alway change according to the tense or aspect that the verb needs to express, adding extra letters to the Chinese character suffices. For those English verbs that use verb endings that trick would work in English as well. For example: the past tense ‘worked’ could be written Japanese style as 働ed. However, not all English verbs take verb endings, and there would be no easy way to indicate the difference between ‘they fall’ and ‘they fell’.⁵
1. ... in Chinese and Japanese.
2. Big disclaimer: I am a student of Japanese, not of Chinese.
3. 昨天 yesterday; 我 I; 洗滌 to wash.
4. 火車 train; 到達 to arrive; 了 marker for completed action.
5. 来る kuru, to come; arrive; 働く hataraku, work.