游泳 (swimming)

我有很多爱好。一个是游泳。

我有很多爱好。其中一个是游泳。   added "其中", the more smooth.

每个礼拜日我走到游泳池。

每个礼拜日我都要去游泳。 if you want to say "i am going to swimming every sunday."

从我的房价需要十五分钟。

从我家到游泳池大约需要十五分钟。

有人认为游泳很无聊可是我喜欢潜水。

有人认为游泳很无聊，可是我很喜欢（泡）在水里的感觉。  "潜水"not equals swimming, i think it equals dive. 

一般我四十分钟游泳然后回来。

一般我游四十分钟就会回家。

这个游泳池很老，可是使用的。

这个游泳池很老，不过还可以使用。

我很早去，所以在回来的路上我买早餐。

我去得很早，所以在回家的路上我可以（顺便）买早餐。

I have many hobbies. One of those hobbies is swimming.
Every Sunday I walk to the swimming pool.
From my house it's about 15mns away.
Some people think swimming is boring but I like being in water.
I usually swim for 40 minutes then I head back.
It's an old swimming pool but it is very practical.
I go early so on the way back I buy breakfast.

family, own value and free.

my favorite actor is Zhou Xing Chi(Stephen Chow), and I feel his best film is A Chinese Odyssey.

在邮局 - 1

明天我要去邮局。

邮局在银行的前面。  I think you want to say is "对面" 

我需要到我的弟弟寄一个包裹。  

我要去给我弟弟寄生日礼物。

我也得买邮票明信片寄到我的家。 这样说也可以，不过我觉得下面这样更好

我也得买邮票和明信片寄给我的家人。   

去了邮局以后，如果下雨我要吃北京烤鸭。

Tomorrow I am going to the post office.

The post office is located in front of the bank.
I need to post a parcel to my brother for his birthday.
I also want to buy some stamps to send postcards to my relatives.
After going to the post office, if it rains I will go eat Beijing roast duck.