A Christmas carol - Chapter 2 & 3

In chapter 2, why is Bob Cratchit cold?

In chapter 2, who is the first visitor to Scrooge's office? Why has he come?

In chapter 2, why isn't Scrooge happy to see him?

In chapter 2, who is the second visitor to Scrooge's office?

In chapter 2, why won't Scrooge help the second visitor?

In chapter 2, why is there lots of food in the shops?

In chapter 2, what are people singing in the streets?

In chapter 3, why does Scrooge look closely at the metal knocker on his big front door?

In chapter 3, what does Scrooge see when he sits by the fire?

In chapter 3, bells ring all over the house. Then they stop ringing. What happens next?