pen是可數還是不可數名詞

Go and get me a pen please.

請你去給我拿支鋼筆來。

I could hear his pen scraping across the paper.

我聽得見他的'鋼筆在紙上沙沙地響。

At the stroke of a pen they removed thousands of people from the welfare system.

他們大筆一揮，就把成千上萬的人排除在福利制度之外。

None of these pens works/ work.

這些鋼筆沒有一支能用。

She reached inside her bag for a pen.

她把手伸到包裏掏鋼筆。