email是可数名词还是不可数名词

I haven't answered her email yet.

我还没有回复她的电邮。

The Net's real killer app is email.

因特网真正的杀手应用软件是邮件。

They sent a global email to all staff.

他们向全体职员发了一封统一的电邮。

They each have their own email address.

他们每个人都有自己的电子邮件地址。

You can send faxes by email from your computer.

你可以通过计算机用电子邮件发送传真信件。