Breakdown of watasi ha asita tomodati no meeru ni henzi wo simasu.
はha
topic particle
私watasi
I
をwo
direct object particle
友達tomodati
friend
のno
possessive case particle
にni
indirect object particle
明日asita
tomorrow
メールmeeru
email
返事henzi
reply
返事 を するhenzi wo suru
to reply
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Questions & Answers about watasi ha asita tomodati no meeru ni henzi wo simasu.
Why is the particle は used after 私 instead of が?
は is the topic marker, indicating that 私 (“I”) is what we’re talking about. In this sentence, you’re announcing what “I” will do tomorrow. が would instead emphasize or introduce a new subject, which isn’t needed here since “I” is already the background topic.
Why is 明日 placed where it is in the sentence? Where do time expressions go in Japanese?
Time words like 明日 (“tomorrow”) usually appear early, often right after the topic (marked by は). Japanese word order is flexible, but a common pattern is:
- Topic (私は)
- Time (明日)
- Location/target (友達のメールに)
- Object (返事を)
- Verb (します)
Moving 明日 elsewhere is possible but less natural.
What does 友達のメール literally mean? Why do we use の here?
の is the possessive/associative particle. 友達のメール literally means “friend’s email.” You’re specifying whose email you’re replying to.
Why is メール marked with に? What role does this particle play here?
に marks the target or recipient of an action. In メールに返事をします, it means “make a reply to the email.” You’re not replying with the email (that would be で); you’re replying to it.
What part of speech is 返事, and why do we need を before します?
返事 is a noun meaning “reply.” When you combine a noun + する to make a verb (“to do X”), you need the object marker を:
返事をする → “to do/make a reply”
Here it’s in polite non-past form: 返事をします.
Why is the verb します in the non-past (present) tense used to talk about a future action?
Japanese non-past tense covers both present and future. The time word 明日 (“tomorrow”) tells you that this します refers to a future action.
Can I say 返信します instead of 返事をします? What’s the difference?
Yes. 返信する is a single suru-verb meaning “to reply (in writing).” It’s a bit more formal or written. 返事をする is more conversational. Both are correct and commonly used.
Do I have to include 私は at the beginning? Can I drop it?
You can omit 私は if context makes it clear who the subject is. 明日友達のメールに返事をします is perfectly natural once the listener knows you’re talking about yourself.
Can I swap メールに and 返事を, e.g. say 返事をメールにします?
Japanese allows some flexibility, but the most natural order before the verb is: target (メールに) → object (返事を) → verb (します). Swapping them sounds awkward. Stick with メールに返事をします for clear, idiomatic Japanese.