write back
phrasal verbwrite back (to somebody)
- to write somebody a letter or an email replying to their letter or email
（给某人）写回信，回复电子邮件 - I'm afraid I never wrote back.
我恐怕从未写过回信。 - She wrote back saying that she couldn't come.
她回信说她来不了。 - She wrote back to him the next day.
她第二天就给他回信了。
- I'm afraid I never wrote back.