[Grammar] The difference between "was" and "is"

[flin8812]

The receptionist said:
What was your SID?
What was your number?

Can't you say "is" instead?

Is this use also similar to the way you use "could" instead "can"
when you're ordering food? That is, "could" being much more polite than "can".

Lots of thanks in advance.

 

[Leandro-Z]

In the case of "can" and "could" it is a matter of politeness and formality. Whereas in "is" and "was" it is particularly the same.

 

[Raymott]

The receptionist said:
What was your SID?
What was your number?

Can't you say "is" instead?
You should say "is". Sometimes, if you're not concentrating, and you aren't sure whether you've been told, you might say, "What was your SID again?", that is, "Please tell me your SID [again, if appropriate]"

Is this use also similar to the way you use "could" instead "can"
when you're ordering food? That is, "could" being much more polite than "can".
It's more polite if they have already told you.

Lots of thanks in advance.

R.

 

[flin8812]

may I ask why "was" and "is" is equivalent in this situation?
There must be a reason why "was" was used instead.