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Do the sentences below have the same meaning?

She's had the flu since last Thursday.
She had the flu since last Thursday.

Do the sentences below have the same meaning?

We have had to work late three times last week.
We had to work late three times last week.

I have another question about the word "and". For example,

Past and Perfect Tenses = past tense and perfect tense?

or does it mean:

Past tense and perfect tenses

Thank you for your help.
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She's had the flu since last Thursday.
She had the flu since last Thursday.
Do the sentences below have the same meaning?-- No; the first suggests she still has the flu, but the second does not.

We have had to work late three times last week.-- No good. A definite past point in time ('last week') invalidates the present perfect.
We had to work late three times last week.-- OK

Past and Perfect Tenses = past tense and perfect tense?-- No, because there is more than one perfect tense. That does not mean that 'and' cannot work like that in other situations, though: 'old and young girls',
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AnonymousShe's had the flu since last Thursday.She had the flu since last Thursday.
Only the first sentence is right.
AnonymousWe have had to work late three times last week.We had to work late three times last week.
Only the second sentence is right as last week is over.
AnonymousPast and Perfect Tenses = past tense and perfect tense?or does it mean:Past tense and perfect tenses
Without more context and complete sentences it's difficult to say anything about the meaning other than the fact that a plural word usually means "more than one". Thus, "the perfect tenses" can be:

He has written a book. (present perfect)

He has been writing a book. (continuous present perfect, the books isn't finished yet)
He had written a book. (past perfect)
He had been writing a book. (continuous past perfect)

CB