English (riddle)

I think the answer of this riddle is raincoat.
Raincoat is made of plastic. 成立
You need me on rainy days. 成立
Because i keep you dry. 成立
You wear me with a pair of boots. 成立
i hope i can help you.
圖片參考：http://tw.yimg.com/i/tw/ugc/rte/smiley_18.gif

應該係Raincoat掛,
因為佢話你要wear住佢,
又係plastic做嘅,
I hope can help u

The answer is

Raincoat

2008-07-19 00:20:00 補充：
I am made of plastic.(我是塑膠造的)
You need me on rainy days(你在雨天需要我)
Because i keep you dry.(因為我可令你保持乾爽)
You wear me with a pair of boots.(你會穿著我和一對靴)
What am I? (我是什麼)

umbrella
-some of them are made of plastic
-u need in rainy days
-avoid u being wet
-after u use, you will put it in plastic bag