If you are looking for specific input values, Numbers, letters, E-mail addresses, and the like, then only allow this type of data and refuse anything else.

如果您期望的是特定的输入值、数字、字母、电子邮件地址等诸如此类的内容，那么就只允许这种类型的数据，并拒绝任何其他东西。

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E-mails are consigning letters to history, and, though Royal Mail is delivering more parcels than before, online and mail-order firms have a widening choice of services to use.

由于电子邮件对传统信件的取代，互联网商行和邮件订购的公司有了更宽广的选择余地，而于此同时，皇家邮政的包裹业务却比以往更多了。

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E-mail isn't replacing all letters and CARDS; partly, it's creating communication that might not have occurred otherwise.

电子邮件没有取代所有的信件和贺卡；某种程度上，它正在创造一种在其他领域都不会产生的交流方式。

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During the months when the self-styled war veterans terrorised farmers and farm workers, e-mail chain letters zoomed around Zimbabwe and to friends abroad, sharing the fears of the people living on the farms.

BBC: Zimbabwe's online campaign

Wendleton recommends sending duplicate letters via e-mail and snail mail.

FORBES: The Shortest Route To A New Job

All four firms are adapting to diminished traffic in letters and important documents because of e-mail, and the growing demand for parcel delivery to end-consumers generated by e-commerce sites such as Amazon.

ECONOMIST: Global express-package companies