Most likely, you will believe that this will take more time than you actually have and you will end up staring blankly at the page as the deadline draws near.
分析主干：you will believe that... and you will end up staring...
本句主句是and 连接两个分句构成的并列句。前一个分句中，that 引导的从句作believe 的宾语，该宾语从句中又包含一个由than 引导的比较状语从句。后一个分句中，谓语部分是end up doing 结构，staring...作主语补足语。
译文：你很有可能会以为这样加工整理素材会让你时间不够用，结果是最后随着交稿日期的逐渐临近，你将只是盯着稿件发呆。