Maybe enjoy the learning - enjoy the journey rather than always waiting to arrive, as you may never get there!  Have fun!

dairy:7.23  Diary - dairy is where cows' milk is made into butter and cheese!  :) 

After several days' work,I am truly tried tired.
I become became a volunteer of SEE (a most influential NGO in China) several days ago. At first I am was very glad to be a member of SEE, for because our group (3 members) is planning setting to set up a social enterprise. It sounds nice good ('nice' is ok, but 'good' sounds better) to set up a enterprise for I am a freshman of university (not quite sure what you mean in this sentence). I wondered whether there are was another Bill arising(ahhhh) [I don't understand this, sorry.]. But then, after several days' work, my dream breaks was shattered! All of last week, I am was making a powerpoint for my leader. I have had modified it more than 10 times! But yesterday he actually rejected my work and ordered me to do another work job for him. Oh no!

(first time to write I have written on italki~)

Well done, and welcome!  I think you have written this all in the present tense - your next step could be to find out about past tense verbs.  When writing, you need to leave a space after most punctuation marks (but brackets are a bit different).  It will make your writing magically look much more fluent!  :)

A present from my sister

Ten years ago, when I finished my university education, my sister gave me a cell phone.  , which It was my first one, as my graduation gift during the commencement. (Not wrong to have such a long sentence, but hard to follow - it's easier to read in two sentences.)  She was working on an ('an' is used before words beginning with vowels - a, e, i, o and u) assembly line in a small factory in GuangDong province, and this phone cost her one month's salary. As a result I was so touched by this valuable present since it was also the most valuable present I had ever received. (You don't need 'as a result' and 'since' in the same sentence.) This was a feature phone produced by a domestic Manufacturer. Of course, in those day, there were no smart phones available on the market. It was an old-fashion flip phone and was only able to could only be used for making calls and sending text messages.
In fact, This phone was particularly precious to me. Just a few days before my commencement, I receive a small postal parcel. When I opened it, there was this cell phone, and a piece of paper, which read:"Dear brother, this is a present for you, good luck after graduation". I was so moved, not only by the electronic devisce, but also the text in the paper.

Very good.  Nice story, too.  :)

Some interesting (and really quite unusual) words here!  I enjoyed thinking about them.

New Words Two

motif
The motif of Moyan's works is the grassroots' life in China's villages

I'd have said that 'theme' or 'topic' fitted that sentence better.

It's a word I've only come across in reading, I think - not one I'd use myself.  I think of it in the context of visual decoration - a repeating part of a pattern.

meet one's mark--I heard this expression from a TED talk, not sure whether it is often used
His early works never met his own mark.

Not a phrase I'd use

convert… into…
Industrialization has converted China from a backward country into an industrial giant.

fine
varsity--rarely seen
He was recommended into the varsity in his third year of college

American.  Not sure how it's used as I'm English!

skew from it
If you want to shoot the target, you need to aim a little bit skew from it.

Ok.  Not commonly used, though 'skew-whiff' (no idea how to spell it!) is used in speech here - eg if a picture isn't quite straight

size sb up--a really interesting expression
They sized me up when passing me.(Is it a neutral word? ) (not sure what you mean)
He spent the evening sizing me up intellectually.-- an example from an online dictionary, can I really use "intellectually" here?
You could, but it would sound rather odd!  It comes up in the phrase 'they sized up the opposition' talking about sports teams or people.
matchstick tip held out at an arm's length
at arm's length (it doesn't have 'an' in the phrase)
draw weight--rarely used?
I can't think of a sentence with this in it!  'Pulling your weight' means playing your part, doing your job effectively.
tenacity
He showed great tenacity during the marathon.
yes - refusal to give up ( Not used much in spoken language though.)
taxed
Climbing up Mount Tai taxed me completely.
Possible, but it would sound better without 'completely'.  It means 'challenged' and 'challenged me completely' just doesn't really work.
star-fished--very vivid
He lay down on the ground, star-fished, gasping; the marathon really taxed him.
Vivid, yes, but it sounds very odd - I've never heard it used like that.  (Also, it doesn't work for me, because star-fish don't have mouths!)
still point of the turning world--poetic expression from a novel
He tried to figure out the still point of turning world, but failed, since he was very dizzy.
I like that.  :)
"It is so rare in American culture, there is so little that is so vocational about it anymore to look at what doggedness looks like with this level of exactitude." A sentence from the TED talk.
Hard for me to understand at the first sight of it. I'm not surprised!  I've read it four times, and still haven't quite figured it out (what is 'it'?)
Can it be transferred this way-- Such doggedness is rarely seen in American culture. Quite possible!

I'm not sure whether you're asking anything about the rest?
align your body posture
align your body posture before shooting the target.
align - line up
glimpse
The simple thought of taking a glimpse of the emperor's tomb motivates the archaeologists to carry on their work.
glimpse - a quick look
riddle
Looking backwards, you will find the path you have gone through is riddled with difficulties and flaws.
riddle - noun - a puzzle (the commonest meaning)

riddle - verb - the meaning here is 'threaded through' or 'filled with'

so much so
He loved his parents, so much so that he sacrificed the opportunity of going abroad in exchange for more company with his family.
He loved his parents so greatly that...
craft
He learned the craft of carving from an hermit in the village.
craft your career
craft - to make or the skill of making
live out
He dreamed of being a scientist, but never lived it out.
I'd rephrase it as 'He had a dream of being a scientist, but never lived it out.'  'it' is 'the dream'

living something out is carrying something out through your life

Thank you for your corrections!

1. First piece of writing!  (not essential, but it sounds better)

Hello everybody!

My name's Marc and my first surname is Martínez, and I was born in Spain. I'm 20 years old. Currently I'm studying the degree of Computer Engineering in the UOC (Open University of Catalonia).

First of all I would will (or I'd like to / I would like to) apologize for my English  (use a full stop or a dash - or a semi-colon; not a comma here) I know it isn't perfect but I'm trying to improve it! This is the reason why I joined in this website!

Secondly I would like to thank all those people who will read and correct my writing! For my part, I will be happy to help you learn and perfect your Spanish level.

Finally, I don't have any idea about how it this will evolve (or maybe turn out - evolve isn't used much in informal language)  this, but I hope we will learn a lot togheter together.

Marc.

¡Fantastico! Mejor que mis español.  :)