Student or Learner
Do I need the second "in" in the sentence below? Thank you.
- I will call you when I come in in the morning.
Same as: I will call you when I come in (the office) in the morning.
Forget any kind of computer grammar checker.
In order to be able to analyse the grammar of a sentence, you must be able to understand it, or at least understand how it is constructed. Computers are not capable of understanding anything.
The fact is that the first "in" belongs to the phrase "come in", and the second "in" belongs to the phrase "in the morning". Both are required.
If you want to avoid having "in in" in your sentence, you can try recasting it slightly: "I will call you in the morning, when I come in."