I work at a desk-job, so I don't get to move around very much.
My two examples say what you want to without directly mentioning the chair or sitting. sed·en·tar·y
ˈsednˌterē/Submit
adjective
(of a person) tending to spend much time seated; somewhat inactive.
synonyms: sitting, seated, desk-bound, stationary; More
(of work or a way of life) characterized by much sitting and little physical exercise.
synonyms: sitting, seated, desk-bound, stationary; More
(of a position) sitting; seated.
synonyms: sitting, seated, desk-bound, stationary; More
Saying that you work a "desk-job" also implies that you sit for extended periods of time.
If you use a phrase like "I'm always at my desk," it is implied that you are usually sitting down. You can say:
- At work, I'm always at my desk.
- When I'm at home, I'm always at my desk. ( <-- using your PC/playing on the Internet)
It is also implied that you are working at a sit-down job if you say, "I don't move much at work."
- I like to go for walks at lunch time because I don't move much at work.
As always, there is also nothing wrong with being direct. Simply saying "I sit down all day" is enough.
- I don't mind standing on the train ride home because I sit down all day.
"I'm always at my desk"と言えばだいたい常に座っているという事です。
このように言います：
- At work, I'm always at my desk.
- When I'm at home, I'm always at my desk. ( <-- パソコンを使っている事)
"I don't move much at work."といえば座りっぱなしの仕事をしていると相手は捉えます。
- I like to go for walks at lunch time because I don't move much at work.
単純に"I sit down all day" で充分だと私は思います。
- I don't mind standing on the train ride home because I sit down all day.
My work requires me to sit in front of my PC all day
I spend most of day in front of the PC
Example:
A: How was your day?
B: Horrible
A: Why?
A: I spent most of my day in front of the PC
Example:
A: How was your day?
B: Horrible
A: Why?
A: I spent most of my day in front of the PC
≪例文≫
A. 今日はどうだった？
B. ひどかったよ。
A. どうして？
B. 殆ど一日パソコンの前で過ごしたよ。
in front of my computer（パソコンの前で）でうまく状況が相手に伝わると思います。
spend＋時間＋動詞ingで「（時間）を〜して費やす」という表現になっています。
all dayをtoo much time（過度の時間）やa lot of time（かなりの時間）のように言い換えてもOKです。
例文は会社に関係なく自宅での状況にもなりますが、office（会社）をあえて用いなくてもどの場面の話であるかは実際のコミュニケーションでは文脈より通じると思います。
officeを用いて、他にも一例を挙げておきますのでご参考ください。
I've been in my office all day, sitting in front of my computer.（[今日は]一日中、パソコンの前に座りっぱなしで会社にこもっています）
I spend most of my time at work sitting in front of the computer.
I'm usually in front of a computer sitting when I'm at work.
When you want to tell someone that you spend a lot of your time sitting in front of a computer at work, then you can say:
-I spend most of my time at work sitting in front of the computer.
-I'm usually sitting in front of a computer when I'm at work.
仕事でコンピューターの前に座っている時間が長いことを伝えたい時、次のように言えます。
-I spend most of my time at work sitting in front of the computer.
仕事では、ほとんどコンピューターの前に座ってます。
-I'm usually sitting in front of a computer when I'm at work.
仕事中は、いつもコンピュータの前に座ってます。
1. sitting on my ass = sitting on my bottom, sitting down. Ass is slang for posteria or bum.
2. sitting on my butt = sitting on my bottom, sitting down. Butt is slang for posteria or bum.
3. 'My work requires me to ____' = You can use this phrase when you want to describe essential activities for your work.
1.sitting on my ass=sitting on my bottom,sitting down. Assは、後部やお尻のスラングです。
2. sitting on my butt =sitting on my bottom, sitting down。Buttは、後部やお尻のスラングです。
3. 'My work requires me to ____' =あなたの仕事に不可欠なことであると説明したいときに使える表現です。
When I am at home I am quite active but at work , I am totally sendentary
Sedentary is the perfect wprd to use in this scenario:-D Those of us who are
"tied to our desks" all day, with little opportunity to move around; are said to be
sendentary... "A desk job like mine is a very sedentary occupation!"
この場合、sendentary(デスクワークの）という言葉がぴったりでしょう。一日中、動き回ることがほとんどなく、机に向かっている人のことをsendentaryと言います。
"A desk job like mine is a very sedentary occupation!"
私がしているような机上の仕事は、まさにデスクワークだ！
カナダ 
アメリカ合衆国 
南アフリカ 
日本 
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