1. When the children looked back at the desert after reaching Archenland, what was the dust storm they could see?

They're helmets - and armour. It's the army. It's Rabadash.

2. What did the lion do to Aravis when she was riding on Hwin?

The lion has only dram his claws across Aravis’s back , Ten scratches sore , but not deep or dangerous.

3.what’s a hermit ?

He had lived a hundred and nine winter in this world who just Live alone in a beautiful place and knowing a lot of things, and learning a lot.

4. When Aravis, Hwin and Bree were staying with the Herm, why was Bree ashamed?

Because he thought that he pretended not to hear Shasta's request, he fled without help from his fellow passengers in danger and Aravis and Hwin were injured.