since and simple tense

Very good question. I can see why this could be confusing.

"Since then" can refer to the past all the way up to the present, which WOULD require the present perfect tense. However, in the sentence above, "Since then" is connecting two PAST tense events. That is why the next sentence states "...symptoms had become," which is the PAST perfect. The writer is recalling the relationship betwe

'Since then' seems unnatural to me.I'd say 'After that' or 'From that time on', or some similar phrase.

cho7712Since then, she noticed that he seemed pale. ...
I was taught to use the perfect tense in the main clause in the case above.

And what case is that? I don't see any particular characteristics of the sentence by which to identify it as a certain 'case'. Is it simply that the sentence starts with 'since then'? I've never heard o

Thank you for the answer. That was my mistake. What I meant was the general rule that says use the perfect tense after the temporal phrase introduced by since. And as you pointed out, the past perfect is what I meant.
Clearly, the second sentence has the past perfect tense, which contrasts against the main clause of the first sentence.

cho7712What I meant was the general rule that says use the perfect tense after the temporal phrase introduced by since.

I think we've found a situation where the general rule does not apply, or at least where it doesn't seem objectionable to violate the rule. Maybe we should keep in mind that the simple past often substitutes for the past perfect, especially

cho7712'Since then, she noticed that he seemed pale. The symptoms had become worse and...'.

I'm confused also. I understand that an event expressed in the past perfect precedes another put in the simple past. But here, the chronology of tenses seems to be reversed.

AnonymousI understand that an event expressed in the past perfect precedes another put in the simple past.

True. She noticed that the symptoms had become worse.

You can't expect her to notice something before it happens, can you?

Thank you all for the answer.
So the time order of the events seems not natural.
For more convenience, I write down the whole context.
'His mother state that for the past three days he had not been behaving like himself. She thought it was because he had taken a long walk on a very hot day. Since then, she noticed that he seemed pale and was having trouble breathing. The

You should note that "since then" does not specify a definite time. It just means "at some time (unspecified) after that", meaning after the long walk. In this context "since then" means little more than "later". Therefore, there is no requirement to use any particular tense. "At some unknown time after he took a walk on a hot day, she noticed that he seemed pale ...".

In long passa

CalifJimIt just means "at some time (unspecified) after that", meaning after the long walk. In this context "since then" means little more than "later".

Thank you for the answer.
I was not able to think of since as unspecified time marker.
According to what said, particular context will specify the meaning of 'since'.