Should the tense of predicate in main clause be the same as the tense of predicate in the relative clause?

Question

It is a very basic question that I need to be confirmed. Consider the following sentence (taken from a book titled Essential Japanese Grammar by Masahiro Tanimori and Eriko Sato).

スミスさんが昨日見た学生は背が高かった。

The relative clause スミスさんが昨日見た modifies 学生 with past tense. The main clause also uses past tense 高かった.

If I translate it to English, it becomes

The student whom Smith saw yesterday was tall.

For me it sounds a bit awkward because the student may no longer be tall now.

Question

• Should the tense in relative clauses agree with the tense in main clause?

• Compare to the previous one, what is the difference in meaning and nuance for スミスさんが昨日見た学生は背が高い。?

Answer 1

In Japanese, the tenses don't need to agree, and in fact, tense mismatches can serve an important purpose.

In English, we have a wide variety of verb tenses, i.e., 3 (past present future) x 4 (simple progressive perfect perfect-progressive) = 12 basic time tenses. Japanese learners of English sometimes wonder why we have so many.

However, consider the following:
"I have not heard that before"
聞いた事がありません

The English version uses perfect present. The Japanese version uses mixed tenses (聞いた is past, ありません is present). So sometimes mixed tenses in Japanese give us additional time-tense flexibility, the same way that the non-simple tenses give us in English!

On a side note, the English non-simple tenses actually have "mixed tenses" hidden in them. E.g., in "have not heard", the "heard" is actually a past-like form called the "past participle", but "have" is present tense.

Answer 2

No, tense doesn't need to agree beyond clauses.

The original sentence refers to smith's memory, rather than a permanent fact. That's why it adopts past tense.