Polite

[Gomery]

I would like to ask someone to confirm somethings.
Which one is more polite?
1. I should be grateful if you would confirm that the contract terms is still valid.
2. Please confirm the contract terms is still valid.
3. The contract terms is still valid?


Thanks

 

[MikeNewYork]

The third is incorrect. It is not in proper question form. The first is more polite and formal than the second, but in both of them the verb should be "are", not "is".

 

[+Technist Warp-]

I would like to ask someone to confirm something.
Which one is more polite?
1. I should be grateful if you would confirm that the contract terms are still valid.
2. Please confirm that the contract terms are still valid.
3. Are the contract terms still valid?


Thanks

The first option would be most polite out of the three options you gave. The second option would be more serious and straight to the point. The third is informal.

Note!
Use 'are' if what it is relating to is plural. Use 'is' if what it is relating to is singular. You could use 'is' if the contract terms were singular -> contract term.

 

[Gomery]

Thank you for your opinion!
I would like to ask when should I use “is/are/am” and when should I use “do/does”?

For the above example, can I write like that “Do the contract terms still valid?”

 

[MikeNewYork]

No. "Do" doesn't work there.

 

[+Technist Warp-]

1. He is funny.
2. They are naughty.
3. I am a student.

Use 'is' when the subject is singular. In the first sentence above, the subject is 'He' which is singular.
Use 'are' when the subject is plural. In the second sentence above, the subject is 'They' which is plural.
Use 'am' when the you use 'I'.

You could also surf the worldwide web for those examples you don't know of.

"Are the contract terms still valid?" work because the subject in the question is 'contract terms'. Using 'do' would be another thing.

 

[Raymott]

I would like to ask when should I use “is/are/am” and when should I use “do/does”?

You should put everything into the indicative (non-question, non-imperative) form first if you are not sure.
For example: if you can recognise "The contract terms are still valid" as correct, you can change it to "Are the contract terms still valid?". These words do not change when you form a question. => "Do these words change when you form a question?" No, they don't.