しないので

1. Is 'しないので' correct to mean "because something didn't exist"? This doesn't seem to be past tense but present tense.
2. I thought "彼たち" means "they". Is 彼ら more common?
3. Is なかったということを too long and confusing? Is it OK?

OK、この段落でこの部分を確認しましょう。
"私たちの時は塾も家庭教師もなかったでしょう。"
これは現在の学生の両親が学生だった時は塾や課外授業が存在しないので、彼らは塾に通ったり、課外授業を受ける必要がなかったということを意味します。

1. It's しない because it's part of the clause 「塾や課外授業が存在しないので、彼らは塾に通ったり、課外授業を受ける 」. That entire clause serves as a description of 必要. It's not really present tense or any tense, it's just a modifying phrase. The larger clause is in the past tense because of 「必要がなかった」.
2. －たち and ーら are both pluralizing suffixes, and are often interchangeable. Which one is used depends on the root word and the specific dialect of the speaker. 彼ら is more common in standard Japanese.
3. 「これは … ということを意味します」is a polite, formal way of saying "This means ... ". There are shorter forms of this structure in casual speech, but using them would change the politeness level of the sentence and isn't always appropriate.

keannu2 said:

1. Is 'しないので' correct to mean "because something didn't exist"? This doesn't seem to be past tense but present tense.

Click to expand...

Both 存在しない and 存在しなかった work well there since 存在する/しない is a state. Refer to the following thread.



As I explained in the thread linked above, the present form and past form are not interchangeable in the following examples.

1. 風邪をひいたので、病院に行く必要がある。
2. 風邪をひいたので、病院に行く必要があった。

#1 必要がある expresses a present condition, and #2 必要があった is a past one. The temporal order of the two events is "風邪をひく" --> "病院に行く必要がある" in both cases, so 風邪をひくので is ungrammatical here.


3.ハワイに行くので、パスポートを取る必要がある。
4.ハワイに行くので、パスポートを取る必要があった。

The temporal order is "パスポートを取る必要がある" --> "ハワイに行く", therefore 行く is used here.
As for #4, even if the speaker already went to Hawaii, 行く is used.
e.g.
高校生のとき、修学旅行でハワイに行くのでパスポートを取る必要があった。