我想問下英文ill同sick既分別

Commonly, Sick and ill are very very similar.
When we talk about our health status, they both means not feeling well. (lack of healthiness)
"I feel SICK." is a commonly sentence in english conversation.
I feel ill is not so commonly said, BUT.... it is also right to say it that way. You can say I will ill as well.
HOWEVER, there is a small difference between sick and ill.
First of all, sick means not feeling well. not happy. It can be both physical and emotional. if you are not feeling happy about something or if something/someone has been bothering you, you can say You feel sick of something, or you feel sick of someone.
eg. I'm sick of my boss. (emotional)
or
I have a back pain, I'm feeling very sick. (physical)
in chinese, sick can be define as 有病,病態 (physcial), ,厭煩(emotional)
the word sick can also used as "home sick". it is also emtional, BUt... it doesn't mean you are not happy or bothered by home. It means you really miss your home/family.
eg. I've been home sick since I'm away from home for awhile.

"ill"
on the other hand means not feeling well (physically). It doesn't mean or do anything with emotional.
if you are feeling ill, it means you have a lack of healthiness. so it means it is a word to describe your health status instead of your emotional status.
eg. I have a bad cold, I'm feeling very ill.
It can also be an adjective of poor or bad. imperfectness or unfriendly, unkind.
eg. Jenn does not have a good relationship with her parents, she behaves ill when talking to them.
In chinese, ill means 生病
and also means 不友善

so the difference between ill and sick is
sick can be define as tired or dislike of something/someone. eg. sick of my friend.
ill can be define as unfriendly, poor, imperfect. eg. she behaves ill.

other than that, if you are not feeling well, like physcially have a cold.
You can use both of them
you can say
I feel ill. or I feel sick. both are fine
but speaking of english conversation commonly, we say I feel sick.

hope that helps

ill同sick都可解作為"生病". i am sick 同 I am ill 都係一樣. 但係文法上sick可以係名詞前, 而ill則唔可以. 例: a sick person. ill 只可用作陳述. 例: i am ill, she looks ill. 可能因為sick都可以用作陳述, 而被廣泛使用

嘩! 你真係問得好. 有時英文都是約定俗成的. 所以用慣了就沒有多想為什麼.
ill 同 sick 某程度上都和病有關, 所以可以共用, 例如:
He is sick. 或
He is ill.

但是sick 並不一定等如病, 還包含唔舒服, 噁心, 厭惡等等的意思. 例如:
He is sick of his boring job.
She felt sick at the sight of the dead rat.(抄自yahoo字典).

希望可以幫到你. ^_^