〔R76〕  My first is a substance that's light;

                 My second makes many things tight;

                 My whole is the key to delight

                 For those with bottles at night.

〔譯註〕 我的第一部分是很輕的東西；

我的第二部分使許多東西緊閉：

我的整體可以打開歡喜

為那些有瓶者，在夜裡。

〔提問〕 If I am a spiral-shaped (螺旋形的) piece of steel (鋼), what am I then?

〔謎底〕  c________