1. The graph shows how house prices have risen since 1980. ( Oxford dictionary, entry: graph)

Does sentence 1 necessarily mean the starting point of rising is 1980? I think it could be applied to the situation where the price didn't rise until, for example, 2000. Just like,

  1. They moved since you left.

It says they moved at a unspecified time after you left. It doesn't have to be immediately after you left.

What do you think? Thanks.

  • 2
    "They moved since you left" is, I think, ambiguous: Since can be used as a conjunction meaning because, so the fact that you left may have been the reason that they moved (because you were the only reason keeping them from moving away). Commented Oct 21, 2022 at 8:50
  • @Peter-ReinstateMonica not ambiguous, but wrong. I read "They moved since you left" as meaning "They moved after you left", which is a common error in some parts of the US.
    – RonJohn
    Commented Oct 21, 2022 at 14:01
  • @RonJohn You mean the temporal meaning is wrong usage? Interesting. As an aside, "common errors" tend to stop being any ;-). Commented Oct 21, 2022 at 15:49
  • @Peter-ReinstateMonica correct. It's possible they moved because you left, but highly unlikely.
    – RonJohn
    Commented Oct 22, 2022 at 1:03

4 Answers 4


The first sentence doesn't necessarily mean that either the rise or the graph starts in 1980. It just means that you can see from the graph how much the prices have risen since 1980.
But, a presenter will usually choose a time span for a graph that highlights what they want to talk about.

For the second sentence, if you mean that they moved at an unspecified time after you left, and the point is that you won't find them there any more, it would usually be said:
They have moved since you left.

If the point is to specify who moved first, you might say
They moved after you left.
and that could refer to any time after.

If you mean immediately, you could say
They moved just after you left.

  • 5
    "It just means that you can see from the graph how much the prices have risen since 1980." <- this is a circular definition Commented Oct 20, 2022 at 14:01
  • From the original sentence, without seeing the graph, I can infer that it has data points showing housing prices, which span a range from 1980 or earlier to a recent point in time, and that the most recent point is higher than the point at 1980. I don't know anything else about the time characteristics of the rise and the resulting shape of the graph. If the example was 'prices have risen sharply since 1980', I would assume a significant slope increase around that year.
    – AShelly
    Commented Oct 20, 2022 at 16:18
  • @user253751 It isn't a definition at all, but a description of the denotation of the first sentence in the OP. That sentence says no more than the description I gave of it. Commented Oct 20, 2022 at 22:24
  • 1
    For the second example, "since" can also be interpreted as causation. A clearer example would be "I'm not going to buy those tickets since you clearly don't like that band". In the used example of "they moved since you left", it's ambiguous as to whether it's denoting the order of events (A before B: "They moved between when you left and now") or causation (B because of A, "They moved because they didn't want to stay there without you"), but given the context the former is more likely to be understood.
    – Flater
    Commented Oct 21, 2022 at 1:25

Sentence 1 says the starting point of the graph is (at least) 1980. It actually doesn't say when, or how prices rose (the graph shows that). Compare with the similar construction "The graph shows if prices have risen since 1980."

But in context, and thinking about prices more than about grammar - I'd expect a graph that goes "up" in a wiggly line.

Generally, perfective sentences with "since" mean "from that point to the present day". So if one says "I've played tennis since 1980", you would understand "I started in 1980 and still play now".


The sentence is ambiguous because of the various meanings of "how", several of which could apply naturally to this sentence.

If "how" means "that" or "the fact that", then the sentence means house prices have risen starting in 1980:

The graph shows (the fact) that house prices have risen since 1980.

But if "how" means "the way in which" or "the degree to which", then it's unclear when house prices started rising, and it's even possible they haven't risen at all since 1980:

The graph shows the degree to which house prices have risen since 1980.


The difference between the two sentences is that the first one is talking about a process that took place over a period of time (prices changing), while the second is talking about something that happened at a single time (someone moving).

When referring to a continuous process with details shown during a time period, "since" usually refers to the beginning of the period being described. If you show a graph with prices over a period of time, it would be unusual and confusing to say "since 1980" if the graph starts at 1990. While the start time given could be approximate (e.g. "since the 1980's"), there's no good reason to say a different time than the graph shows.

But when talking about a single event, "since" merely refers to some notable time before the event. In your second example, the time when someone left is an important starting time for a period, and the other event "they moved" happened at some time after that.

Note that even when you're talking about a continuous process, the first interpretation only applies if you're actually giving details. You can also make approximate statements like

Home prices have increased significantly since the 20th century.

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