[Google] Play Books送$5 credit

Google Play五岁生日了，现在可以在其页面醒目位置领取Book区$5 credit（或者点击以下链接），大概几分几毛就能买到一本英文书籍，就当是锻炼一下英语阅读吧。

https://play.google.com/store?code=F7BDGET17A4UNMFVU0K2A8Z&pcampaignid=V-4_TYPE-StratPromo_LANG-En_GEO-Ca_CAMP-10030308_CHAN-Email_DATE-20170306_MSG-100058102_SUBJ-General_SUBTYPE-Crit_EXP-None_OFR-Cc_TRT-M_LOC-2_MOD-text_CORP-Books_SLOT-CTA