Earlier while chatting, I wrote a sentence and a native speaker told me it was correct. The sentence was:
某天我去北京。= Someday I'll go to Beijing.
(mǒu tiān wǒ qù Běi jīng)
I noticed that no prepositions are used here. It's probably because I'm still a beginner, but then I wondered: if it's true that 到 can mean "to (a place)", why isn't it used in that sentence? Are there some rules I'm not aware of or something I'm missing?
Also: when should we use 到? What are the situations/contexts that need it?
First, grammars of Chinese and English are totally different, you don't need the preposition like in English.
Second, in my opinion, 去 indicates that you start the action of "going to a place",and "到" indicates that you have finished that action, so you "reach a place " or "arrive at a place".
An example:
本周二我会坐火车去北京，周三到。
I will go to Beijing by train this Tuesday and I will arrive on Wednesday.
A significant difference between Chinese and English is that sometimes the border between a "verb" and a "preposition" is blurred. In your case, both "去" and "到" has the meaning of "go", "go to", "reach", or "visit", and therefore can be used interchangeably.
You don't need a preposition if you use a transitive verb to translate "去": 某天我去北京。 = Some day I'll visit Beijing.
<beginner>The second version (某天我到北京) sounds to me like "I was in Beijing one unspecified day in the past" or maybe "I came to Beijing one day"?</beginner> Hopefully, someone will clarify..
Dec 17, 2011 at 14:22
到 more or less means "to arrive (at)," 去 means "go to (someplace)."
E.g., 你到18歲才能喝酒。You can drink alcohol, when you are (lit. "arrive at") (the age of) 18.
When used together with 去 (e.g., 到马路那边去), it tells someone to go somewhere or do something.
Huang and Krazer's answers already point you in the right direction.
I cannot find an example where 到 alone means to go.
You should use 到 (when alone) has you would use the verb arrive in English.
到家我要睡觉. When I arrive home (when I am back at home) I need to sleep.
我到北京了. I arrived at Beijing.
到 indicates a final point, a destination.
It can also be used in combination with 去 to indicate the final destination of a journey (more or less long distance) and thus add the idea of movement, travel.
Note the nuance in the following examples:
我去北京. I (will) go to Beijing.
我到北京去. I (will) travel to Beijing.
某天我去北京 is arguably wrong due to the lack of any indication of tense. I will not be able to determine from this sentence the tense, therefore I will not know what exactly are you trying to say.
某天我去到北京 will be interpreted as past tense, since 去到 essentially means "arrived at".
某天我会去北京的 will be interpreted as future tense. 会+verb means something you are going to do (or have planned to do).
I guess the use of 某天 ruled out present tense.
Also note that, "someday" in English usually indicates a day in the future (Someday, I will beat you in Chess!). However 某天 is NOT exactly the same because it can refer to any day, past or future. So 某天 is more like "one day" in English.
So, your sentence would actually be interpreted as:
One day, I [go/went/will go] to Beijing.
Hence the doubt.
某天我去北京 = 某天我将去北京
我将在未来某个目前还没有确定的时间，去北京。
