一般过去时被动语态形式是什么

应该是was / were + done
e.g. I was taught by Miss Zhao last year.
去年，我是由赵老师教的。
Those letters were wirtten by a famous writer.
那些信是由一位有名作家写的。

was/were+done(动词的过去分词),选择was+done还是were+done是由主语的单复数决的 比如they were taught. she was taught. it was written

was/were+动词过去分词。
比如说: 1.water的过去分词是watered
eg:The trees were watered by Lily.
2.write的过去分词是written
eg:The letter was written by Tom.