关于时态,麻烦分析一下句子结构

题目

关于时态,麻烦分析一下句子结构
Physical copies only started pressing on Friday morning,and are expected in shops on 21 December.请问 started 是过去时作谓语?那后面的are expected 为什么不用过去时态,前后保持一致呢?

答案

Physical copies only started pressing on Friday morning, and are expected in shops on 21 December.两部分时态不同,句子表达意思有变化.句子意思为：物理副本在（刚过去的）星期五早晨才开始印刷,而据（现在）...