When the dog asks for something

We have been caring for dogs since 1996 so we are kind of used to the behavior of dogs. When they are hungry, we would see the tongue licking the lips which means the dog wants food. Almost the same when they want to drink but they go to the cabinet of the dish bowls. And when they want to go out they whine a bit in front of the door.

But sometimes our dog would sit in front of us then whine as if asking for something. When we do not know what the dog wants then we get a bit alarmed. Sometimes the dog is sick so we should be aware of that.