thank you very much. Can you comment on these sentences?
1. Since 1998, UT admissions does not require top-10 percenters to submit any test scores, although most do.
(here I don't understand why simple present is used instead of present perfect)
here
2. Indeed, to Telli's knowledge, no-one from the settlement had ever even seen a human being from outside the community since their ancestors had arrived there with Drakis the prophet three centuries before.
(here it seems to me as if the use of "had arrived" after "since" is natural, but you considered "I hadn't seen them since they had been married" wrong. Then, would this be correct too: "I hadn't seen them since they had been married three years before.")
here
3. Has anyone ever escaped the Khrelling since you have been here, Seth?
( Why not "were" instead of "have been" after "since"?
here
4. He ate well for the first time since he had left the camp for his last shift of work.
(to me, this is the weirdest one. O wonder whether "since" here is used as a time conjunction or reason conjunction. If time conjunction, how can you explain its use in this sequence? "simple past // since // past perfect"
here
5. By now most language teachers in the United States and Canada have heard about my Total Physical Response (TPR) approach. (Asher)
(here is it possible to use any other tenses instead of present perfect?)
6. I am the legitimate candidate for it since 1998.
(here is it corect to use "am"?)
7. We lead a very quiet life since Ralph retired.
(Is "since" a reason conjunction here? If it is a time conjunction, is there anything wrong with tense choices?"