单选题Zheng says that the 

问题补充：

单选题Zhengsaysthatthemostdangerousthingaboutacreditcardis____apersonisn’talwaysawareofthefact____he’sspendingmoney.A.that; thatB.what; thatC.that; whatD.what; which

答案：

A解析____ a person isn’t always aware of the fact是表语从句，且句意完整，用that引导；____ he’s spending money是the fact的同位语从句，语意完整，用that引导。所以选A。