Sequence of tenses: I thought it was going to rain, but it didn't...

[Saneta]

1.a) I think it is going to rain.
b) I thought it was going to rain, but it didn't.
2.a) I think Mark is friendly.
b) I used to think Mark was unfriendly.

Please tell me are the sentences b) examples of sequence of tenses?

1.b)does this sentence mean the situation:, I thought (in the pasat):,, It is going to rain.'' '
2.b) does this sentence mean the situation:, I used to think:,, Mark is unfriedly''.'

thanks!:)

[Mister Micawber]

Yes and yes, but a clearer word is 'backshifting'.
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Native English teacher at Mister Micawber's