请考虑下列两组叙述句改成疑问句:
1. Mary said that she saw John yesterday.
2. Who did Mary say that she saw?
这里 1 和 2 文法都是正确的.
3. Mary said that John saw her yesterday.
4. Who did Mary say that saw her?
这里 3 是对的, 但 4 是错的, 要写成如下才对.
5. Who did Mary say saw her?
母语人士会直觉 4 就是错的, 非母语人士则否.
请问有无方法用传统文法向学生解释呢?
若用 wh-movement 和 that-trace 怕会更糟吧.
Thanks in advance.

我觉得把 that-trace 当作是一种 descriptive filter也未尝不可。Wh-movement 跟 trace 应该在学习造问句时就有点基本概念了。

母语小朋友看到 sentence diagram 心情都不美丽了; 非母语小朋友看到更难的 syntax tree 恐怕就和我翻脸啦.

你那句子，到底谁才是句子的主词？是Who还是Mary?

一楼 r 大是位行家, 立刻看出这是 prescriptive 和 descriptive 之间的矛盾. 这并不是把它当作陷阱题来刁难各位,而是因为非母语学生都是透过 prescriptive grammar 学习英文, 要如何教导这种句型会让人感到困扰, 无法单用 usage 解释 (蒙混) 过去. 退一步想, 这些都是常见的句子, 如果考试时被 (刻意或无意地) 出成题目, 老师要如何解释答案呢?

现在的小朋友要学这的文法？(接这卡通歌词[0:26]处)https://youtu.be/B5ziDTP4fyE?t=26

母语小朋友不用学 (那虚无缥缈的语感又出现啦), 非母语小朋友的话... 老师教错就会学错, 所以是老师应该学, 但要怎么教小朋友是个问题 (当然不能硬教 generative syntax), 毕竟这些都是生活中常见的句子, 不是吗?

只有我觉得时间轴怪吗？Mary said that she’d seen….

直述和间接转述的时间轴考量是不同的, 所以下列四个都对,但语意不同.Mary said that she saw John.Mary said that she had seen John.Mary said that she would see John.Mary said that she will see John.后两句的差别是 "计划遇见/拜访John" 的时间点, 一个已过, 一个未到.另外加赠四个长得有点像, 但不是间接转述的例子:Mary would say that she saw John.Mary would say that she had seen John.Mary will say that she saw John.Mary will say that she had seen John.有疑惑时, 建议把可能都列举出来, 一一检视对错, 就更不容易忘记.