Who can help me to explain some quotes in Walden :(

"Most men, even in this comparatively free country, through mere ignorance and mistake, are so occupied with the factitious cares and superfluously coarse labors of life that its finer fruits cannot be plucked by them"

"There is no odor so bad as that which arises from goodness tainted. It is human, it is divine, carrion. If I knew for a certainly that a man was coming to my house with the conscious design of doing me good, I should run for my life, as from that dry and parching wind of the African deserts called the simoom, which fills the mouth and nose and ears and eyes with dust till you are suffocated, for fear that I should get some of his good done to me,-some of its virus mingled with my blood"

"What is true for one is truer still for a thousand, as a large house is not more expensive than a small one in proportion to its size, since one roof may cover, one cellar underlie, and one wall separate several apartments"

"Most men, even in this comparatively free country, through mere ignorance and mistake, are so occupied with the factitious cares and superfluously coarse labors of life that its finer fruits cannot be plucked by them"

Well, this may be "serendipity" as yours truly happens to be re-reading the book now.
This first quotation seems reasonable to me.
I think Thoreau means that we are so preoccupied and busy with acquiring material goods and wealth that we don't take time to appreciate the finer things of live, the beauty and riches of Nature unfolding before our very eyes.
These "finer fruits" (an example of synecdoche as well as a gorgeous metaphor) refer to those features of Nature.

"There is no odor so bad as that which arises from goodness tainted. It is human, it is divine, carrion. If I knew for a certainly that a man was coming to my house with the conscious design of doing me good, I should run for my life, as from that dry and parching wind of the African deserts called the simoom, which fills the mouth and nose and ears and eyes with dust till you are suffocated, for fear that I should get some of his good done to me,-some of its virus mingled with my blood"


Aw, this is Thoreau's under-rated but very acute sense of humor at work here. What wit! Beware of people who tell you things for "your own good." And there was a sarcastic joke flying around not long ago: "We're from the
government and we're here to help you." What that joke--and Thoreau seems to be saying is-- if someone says he wants to "help" you, head for the hills. Think of all the damage that has been done to society by those who think they are doing "good."


"What is true for one is truer still for a thousand, as a large house is not more expensive than a small one in proportion to its size, since one roof may cover, one cellar underlie, and one wall separate several apartments"

This is the most difficult one of the three.
In a broad sense, what he seems to be saying is that the
statements he has been making should hold true no matter what the circumstances.
Or more specifically he might be saying that a large expensive house is just as good as a cheap one -- for the
recurrent theme throughout Walden is a disdain for materialism, how a dependence on acquiring things can be oppressive. "Simplify!" "Simplify!"

Hope these responses help.
Auntie

"Most men, even in this comparatively free country, through mere ignorance and mistake, are so occupied with the factitious cares and superfluously coarse labors of life that its finer fruits cannot be plucked by them"

He really contradicted himself with that quote, since later in the book he goes on about the virtues of working on a farm and hard labor.

Sort of. . . Walden is an experiment at trying to find the best life. And Walden, the book, is Thoreau's documentation of his experiment at living the best life. As a result, many places in Walden where Thoreau appears to be hypocritical, he is merely documenting a failed experiment.

In the passage that you cite "so occupied with the factitious cares and superfluously" (my emphasis) Thoreau identifies that the problem with labor, in this case, is not labor itself, but the intense occupation with it. Thoreau later extols the virtue of labor and farming, yes, but via experiment and failure, he feels that his has discovered the best ways (emotional/spiritual) and the best methods of farming.

You may find that in Walden, Thoreau does nearly everything some one living "normally" would do: he has a garden, he goes to town, he participates in meetings, he goes on fishing excursions, he reads, he writes, he visits friends. . . . . and yet he is critical of the manner in which each one of these activities is conducted in common society.

This is a bit off the OP but I have to point out that Thoreau left Walden and went into town all the time. While he was there, he still worked in his family's pencil-making business. Indeed, while here he developed a process to so finely mill graphite that the family business expanded into printer's ink. He enabled his family to make a fortune.

He went into the woods to live deliberately but for a reason. He wished to finish his studies. He had two options: the traditional way of work and save for years and then leave for study full time; or cut expenses to the essentials and complete his studies right away. He went to Walden and did the latter. The book was a bonus.

It is necessary, first of all, to bear in mind that Thoreau wrote the whole book with a sense of humour. His purpose in writing this book is also very often misunderstood. Thoreau wants the readers who do not share his views to understand his intention when he says that he does not mean to prescribe rules to strong and valiant natures who will mind their "own affairs" whether in heaven or hell and build more magnificently and spend more lavishly than the richest without even impoverishing not knowing how they live...."I do not speak to those who are well employed...but mainly to the mass of men who, are discontented, and idly complaining of the hardness of their lot....I also have in mind that seemingly but most terribly impoverished class of all, who have accumulated dross, but know not how to use it, or get rid of it, and thus have forgotten their own golden or silver fetters"
Another important thing which we must bear in mind is that he is not asking us to abandon our cities and our homes, and go out into the wilderness to live in huts and meditate on nature. Thoreau makes it clear that he does not want all his readers to adopt his way of living. " I would not have any one adopt my mode of living on any account; for besides that before he has fairly learned it I may have found out another for myself"
In an age of collectivism, Thorasu's words have great relevance. This is not the advice given to us by an abolitionist. On the contrary, the author of "Walden" is an anarchist who wants every individual to keep his individuality free from the influence of traditional views and prejudices.