key是可数还是不可数

是可数名词，复数形式是keys，例如：

1.Let yourself out and post the keys through the letter box.你先出去，再把这些钥匙塞进信箱吧。

2.Typically, she couldn't find her keys.她果然又找不着自己的钥匙了。

3.I can't think where I put the keys.我想不起把钥匙放哪儿了。