不是吧,它那是举例而已,原文如下:Expiration of Form W-8BEN. Generally, a Form W-8BEN will remain in effect for purposes of establishing foreign status for a period starting on the date the form is signedand ending on the last day of the third succeedingcalendar year, unless a change in circumstances makes any information on the form incorrect. For example, a Form W-8BEN signed on September 30, 2015, remains valid through December 31, 2018.