改善英文行動三. 希望大家盡力幫忙

Hello! (a space has to be left after a punctuation)I am John. I am 17 years old. I like watching (you can use either watching or to watch, but you cannot just use “I like watch”) animal (??), do you have the (we use the because this is a specific habit, not general) same habit like me? I have a younger brother David whose character (mannerism is a word seldom used nowadays) is totally different from me. He is rude and has bad temper.(But you have not mentioned your character, you just told us some facts of yours like age, habit, etc., so when you say David has a different character and said that he is rude, etc., you should also state something about your character at the beginning) Also, he always go out to meet (remember the rule : to-infinitive) his friends at night. I am afraid he will become a gangster. He was spoiled by my parents because he is the youngest in our family. I hope he will (no be – because you are not using passive voice) change in the future.
Notes :
- Try not to start each sentence by – I am / I have / I …., because this will divide your whole paragraph into separate parts without connection. Try to use more connectives such as : and, when, however, etc.
- I know you are just writing a paragraph for people to correct, but still you need to have a major subject in your paragraph, e.g. my habit / my family / my brother / Me / etc. From your paragraph I really do not know what you wanted to say – I mean your main content. The main thing in writing is to let your reader know what you want to tell them.

Hope above helps !

(1)
...like watch...

I like TO watch/like WATCHING...

(2)
...do you have same habit with me?

...do you have THE same HOBBY AS WELL?

habit習慣
hobby興趣、愛好

(3)
I have a brother David whose mannerism is totally different to me.

... a brother CALLED David
or
... a brother, David, whose
and
... MANNERIAMS ARE totally different FROM me.

(4)
He is rude and have bad temper.

... and BAD-TEMPERED.
or
... and HAS A bad temper.

(5)
...he always go out to met his friends at night.

...always GOES out to MEET his...

(6)
... am afraid he will become bad

... afraid THAT he will...

(7)
... hope he will be change in the future.

... he WILL CHANGE...