11. An ________ of the post’s fundamental role in the creation of the United States requires a little knowledge of the problems faced by the colonies at that time.
12. In 1691, to boost trade and ensure its control of North America, Britain ________ a centralized postal system.
13. By the mid-eighteenth century, this ________ network push thirteen quarrelsome provinces toward developing a new, independent-minded, egalitarian culture more American than British.
14. America’s first political cartoon ________ in the newspaper.
raise ________.">15. Stamp Act is a law passed by the British Parliament in 1765 to raise ________.
raise ________." />
16. Meanwhile England ________ and searched mail for seditious content.
17. The awful roads developed the provinces’ sense of isolation and ________.
RFID拥有耐环境性、穿透性、多样化等特点。
EAN编码的长度是固定的，只能有13位。
二维码就是QR码。
我国的北斗导航定位系统目前只能覆盖到亚洲区域。
QR码是一种堆叠式/行排式二维码
COO定位是以一种单基站定位方法
一维条形码中对光线反射率较高的部分为条
QR码的纠错码可以纠正拒读错误和替代错误。