All of the nouns used (hammer, chain, furnace, brain, anvil) are explaining mighty things that the tiger is being compared to. The poem is simply saying that they are smart, speedy, and strong.
I hope this helped! If you have further questions don't be afraid to ask!
~Travis
I would say read closely and highlight any important details. If the textbook belongs to the school and you're not allowed to write on it, take some notes and write down the important details on a different piece of paper.
The technical meaning of care is a state of mind in which one is troubled;worry,anxiety, or concern