Why 了 in 走+time+就到了？

Question

I came across the following sentence:

她的家很近，走五分钟就到了。

Tā de jiā hěn jìn, zǒu wǔ fēnzhōnɡ jiù dào le.

Her house is very close, only need to walk for five minutes to arrive.

Question: Why is there a particle 了 at the end?

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First, I thought this 了 could mean completion (see Expressing completion with le in resources.allsetlearning.com ) of the action walk for five minutes and arrive. But then I also saw this sentence:

我的公司很远，走路要一个小时。

Wǒ de ɡōnɡsī hěn yuǎn, zǒulù yào yí ɡè xiǎo shí.

My company is far away, it takes me an hour to walk there.

Which is quite similar in meaning (I could understand also the action of it takes me an hour to walk there is completed), but doesn't have the particle 了.

Answer 1

了 at the end of a sentence is (most often) a modal particle that indicates change of state.

In your example sentence:

... 走五分钟就到了

it marks the change of state that occurs when, after walking for five minutes (original state, walking), you arrive at your destination (change of state, arrived).

This use of 了 is common in:

1. expressions involving time, because the passing of time often involves state changes: 我等了一个小时的车了, "I waited (original state) the bus one hour (change of state, not waiting anymore)"

2. commands, as they imply a change of state as soon as the command is executed: 你闭嘴了, "Shut up!" (talking, original state, to not talking, change)

3. 'going to' forms with 要～了 or 快～了, as they imply an imminent change in the future: 今天要下雨了 "It's going to rain, today" (not raining, original state, to raining, change)

You can also find a nice explanation of different flavors of 了 here.

Answer 2

了 in 她的家很近，走五分钟就到了 can be a verb particle for 到 (indicate the verb 到 is a completed action). It can also be a modal/final particle that put emphasis to the sentence

要(need) in 我的公司很远，走路要一个小时 indicates it is a 'constant', No matter how many time you walk to your company, you still need about an hour. The situation therefore, no change, and the verb particle 了 that indicate 'change of situation' is not applicable

Since it is a constant, the action is not a completion, the verb particle 了 that 'indicates completion of a verb' is not applicable neither

If you use 了 as a modal/final particle, 我的公司很远，走路要一个小时(了) also doesn't sound right, because it is an incorrect choice of modal/final particle. It should be 呢 e.g. 我的公司很远，走路要一个小时呢!

modal/final particle

Answer 3

Like many other sentence final particles (e.g. 吗，呢), 了 is mostly used in interlocutionary scenarios where the locutor and the interlocutor interact to determine the sense of the discourse.

In the case of 了, we have a scenario like this:

• Firstly, a time zone T (usually tied to the moment of locution T0) is susceptible of locating a process P (i.e. an action or event). In other words, the locutor assumes that the interlocutor expects P to happen.
• The locutor then asserts that T indeed locates P.

For example:

1. 他们来了，快去开门! Here they come. Open the door, quick! (We have been waiting for them, and here they come at last.)
2. 这本书我看过了。I have already read this book. (You advice/expect me to read this book, but I have already read it.)

Sometimes, T can be a projected time. For example:

3. 火车站？不远。前面街口右拐，一直走，大概十分钟就到了。

3a. 火车站？挺远的。前面街口右拐，一直走，大概要半个小时才到。

In (3), 了 is used when the temporal location of P falls within expectation (due to the function of 就: "sooner than you would expect").

In (3a), 了 cannot be used when the temporal location of P falls out of expectation (due to the function of 才: "later than you would expect").

Answer 4

走五分钟就到了，突出的是时间短，而且那个人可能已经走过一次，他“到过”，所以才这么肯定地用“到了”。走路要一个小时，更能突出时间长，表达的是路比较远

It's only five minutes' walk. The outstanding thing is that the time is short, and the person may have passed it once. He "arrived", so he used "arrived" so definitely. It takes an hour to walk, which is more outstanding. It takes a long time to walk