I. Grammar Stage Inquiry
What is the most important event?
Since the most important event is suppose to drastically change the main character(s), I believe it is when an adder bites Mrs. Yeobright and she dies on the Heath. Afterward, Clym learns that his mother felt rejected by him, and he carries the burden of guilt of her death. This causes him to withdraw from people and become bedridden. And it snowballs from there.
After several weeks, he recovers his strength and tends to his duties to prepare his mother’s home; however, he hears additional information from others about her final days, and he investigates further to learn that Eustacia did not tell him what she knew. This causes him to rightly lash out at his wife, and even to feel violently toward her. She leaves him.
Days later, when he feels regretful of how he treated her, he writes a love letter asking her to return to him. But it is too late. When she drowns in the weir, he feels responsible for another woman’s death. He withdraws to himself again, and somewhat trades places with Diggory, who now settles down with Thomasin, while Clym chooses to wander the Heath as a preacher just as Diggory did as a reddleman. I don’t know if he will ever be capable of love again.
As for Eustacia, who is considered another main character, the only thing she wants to do is leave the Heath, which is why she marries Clym; but after his mother’s death, everything changes. Later, she knows Wildeve has money to help her, but if she has to rely on him, he is not good enough for her. It is possible she felt like she had no recourse, and that would support why she jumped into the weir to drown.