to answer something; to return a call

three times; thrice

to ask

lost and found

cell phone; mobile phone

cell phone number; mobile phone number

to listen to; to hear

I am 23 years old.

zero

radio

to speak with someone

telephone number

My telephone number is...

What is your telephone number? (informal)

What is your telephone number? (formal)

to lose something

important

How old are you? (informal)

How old are you? (formal)

twice