科技英语的一个重要的，也许是令人惊奇的特点是：无论是书面的传达，还是口头的交流，二者都是可以作为正式文体而通用的。
An important and perhaps surprising feature of technical English is that its normal style is common to both written and spoken communication.
担保一种字据或保证，通常为书面的，以保证某种产品或服务的质量或耐用性
A promise or an assurance, especially one given in writing, that attests to the quality or durability of a product or service.
口头的用口讲出或证实的；非书面的
Expressed or evidenced by word of mouth; not written.
你必须得到他书面的同意。
You must get his agreement in writing.
