Difference between two sentences?

Hey guys does anyone know if there’s any difference between these two sentences or if one of them is grammatically incorrect?



Thanks in advance!

first one means “when you study, it is okay to use a dictionary”
2nd one means “when studying, it is okay to use a dictionary”

Am not the best at grammar, but I do believe, except when spoken casually, the first sentence should have “wo” in between benkyou and suru

WK teaches “勉強する” as a proper verb.

I think both sentences are grammatically correct and make sense in this case. The difference is one of emphasis and use cases.

勉強する時 can generally mean ‘study time’, kinda like ‘when you study’, and can be used both for something that happens (just) before you study and something that typically happens when you study. It’s good for general statements like the one you made above, or for habits like ‘when(ever) I study, I have coffee’: 勉強する時、コーヒーを飲みます。I think something like ‘when you study, look for a quiet place’ works well as well: 勉強する時、静かな場所を探してください。

On the other hand, 勉強している時 emphasises the period during which studying is being done, meaning that what comes next has to be something that happens at the same time. For example, 勉強している時、電話がかってきました。= ‘While I was studying, the phone rang [literally “came ringing”].’ In the case of your second sentence, what’s being indicated is that while studying, a dictionary is being used simultaneously, and that’s acceptable. Also, I have the impression (though this may not be true) that your second sentence suggests that the dictionary is being used frequently throughout the study session, whereas your first sentence applies even if the dictionary is only used once or twice during the study session. I might just be splitting hairs though.

Generally speaking:

  • 〜う form (i.e. plain present/future form, aka dictionary form) + 時 = ‘when(ever) ~’ or ‘before ~’
  • 〜ている form (i.e. present continuous form) + 時 = ‘while ~’
  • 〜た form + 時 = ‘after ~’ or ‘at the point when ~ was finished’ (e.g. 帰った時、お母さんがいました = when I got home, mum was there.)
  • 〜ていた form + 時 = same thing as 〜ている時, except that it’s only used for past events. (At the least, I can’t think of a case in which it makes sense for present events.) When past events are in the main clause (i.e. the one that comes after the ‘while/when’ clause), 〜ている時 and 〜ていた時 are equivalent, possibly with just a difference in emphasis on the ‘past’ nature of the actions.

Yup, it is. Specifically, it’s part of a whole family called ‘する verbs’, which are formed by attaching する to kanji that typically describe actions or states. It’s not wrong to say 勉強をする, but 勉強する can function as a single unit without any particles in between.


About the を thing, it matters when you explicitly mention what is being studied.

You can say

Of course the を tends to get dropped in conversation so it doesn’t much matter either way, but in writing it’s important to make sure it goes in the right place.


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