Hello,Mr.Matthews.
I want to ask you if conj.since can be replaced by because and as.
e.I didn't go to school since I was ill.
.
In another example after or since, maybe both ?
Ann was happy ... she passed the interview.
Thank you.

No, you can't use "since" in its time-reference sense with the simple past tense. It normally requires the perfect tense.

I didn't go haven't been to school since I became ill.
I didn't see haven't seen her since the accident.

"Since" in its sense of reason can be replaced with "because" and "as":

I can't go today, since/because/as I've got to work.
Ann was happy since/because/as she passed the interview


PaulM

1.Can we use who question for animals?




e.g.I fed the qeese.Who/What did I feed?

2."Where" can't be used with the verb visit.Is it so?

Recently I have met a number of nouns with suffixes -er,-ar etc.I didn't know that they
are derivative nouns.
,e.g.planet,sugar,basket,cement,instrument and so on.IT was given in USEFUL ENGLISH
I DOUBT WHETHER IT IS correct or not.
But I didn,t come across the suffix -ire as in millionaire.Is it a derivative word?

No, the examples you cite are not derivatives since their endings are not actually suffixes.

"Millionaire" has the suffix -aire found in loanwords from French and which is used to denote someone who has a million pounds or dollars: "million + -aire"

Other examples of loanwords from French include: "concessionaire", "doctrinaire", "commissionaire" "and "legionnaire".



PaulM