pt代表动词的过去时形式，是past tense的首字母缩写。例句：Listen, point and find words in the past tense.听，指出并找到用过去时态的词。
例句
1、Do you know how to form the past tense?
你知道怎样构成过去时吗？
2、You have to use the past tense.
要使用过去时。
3、It was as though Corinne was already dead: they were speaking of her in the past tense.
科琳娜好像已经去世了：他们谈论她时用的是过去时。
4、In narrative, the reporting verb is in the past tense.
在叙述过程中，间接引语的动词通常用过去式。
5、A Semantic Study of the English Simple Past Tense and the Present Perfect
实话英语的时态一般过去时和现在完成体的语义研究。