What are they doing?
They are speaking on their mobile phones
'What is the person doing?
He / She is sending a letter
What do you need to do?
You call back later
What is she doing?
She's writing an email
What is happening?
The phone is ringing
What is he doing?
He's sending a text message / He's texting
'What is he doing?
He's speaking on his landline
What is she doing?
She's leaving a voice message
What are they doing?
They're charging their phone
What is happening?
They have bad reception / They don't have reception / They have no reception / There's no reception
What is happening?
They are topping up the phone
What is he doing?
He's dialing a number
What are they doing?
They're using social media
What are they doing?
They're videochatting
What are they doing?
They're talking face to face