Usage of since

[Ofriendragon]

9. My doctor has written to them frequently since they lived in New York.
10. I have lived here since I was a child.

In these two sentences, the time spans that since expresses are different.
Sentence9 means
My doctor began to write to them from the point of time when they left New York while

Sentence 10 means
I began to live here from the point of time when I was a child. Am I right?

Many many thanks.

[Yankee]

Hi Ofriendragon

Your usage of since is OK and your understanding of the time frames involved is basically correct.

In sentence 9, the meaning would be a little clearer if you said "since they left New York" or "since they moved to XXX".

In sentence 10, the past "point in time" is a very large "point" because it consists of a number of years. The speaker began to 'live here' during childhood. It's not possible to say exactly how old the speaker was at the time. We only know that the speaker was quite young.
.