I expect the sign of βthree is optimistic, the indicator of βfive is destructive, the conversation time period capturing the influence of selling price on complete revenue is impacted by advertising and marketing and affect of marketing on complete earnings is influenced by value. 曾經接受代寫服務的阿瑩（化名）指，代筆寫手逾期交文，更從網上直接抄襲部分內容，認為「槍手」質素難有保證。... http://martinj88rq.tblogz.com/an-overview-25229703