首先，它们允许你在不同的网上书店选购电子书，许多还都有促销优惠。

First, they let you shop around fore-books at different online bookstores, and many run promotions.

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在社交网站上关注品牌的原因，认为是为了获得更多的促销优惠和产品信息的人最多。

The most popular reason for people to follow brands on social networks is to find out about promotional offers and sales.

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您只要登记申请我们的会员卡，这手续是免费的，然后您就有权利享受我们今天的特别促销优惠了。

All you have to do is sign up for our membership card, for free, and you're entitled to take advantage of our special offer today.

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