For two years Thoreau lived by the shore of Walden Pond by <span>C. working the land by himself.
It was a kind of experiments for him, a simple life at Walden Pond. He used this experience to write about and describe its philosophy of life, politics, and nature. This inspired his work "Walden" </span>
If you did means it would be past tense. If you do it means you’re doing it in the moment. AKA present tense
Its using a comma before a conjunctive adverb.
In this scene, Helena is speaking to <span>Lysander and Demetrius in a Midsummer Night's Dream.</span>