What you will need: a nine volt battery, two pencils, a piece of cardboard, a glass of warm water, some salt and about 50cm of wire.是什么意思_What you will need: a nine volt battery, two pencils, a piece of cardboard, a glass of warm water, some salt and about 50cm of wire.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句