Is it grammatically correct to leave out in and write "She told her to phone him the morning of the next day" instead of "She told her to phone him in the morning of the next day"?
If not, why not, and does that rule have a name?
My English teacher (not a native English speaker) tells me it is wrong and that in must be in that sentence, but I don't get why.
The task was to transform
Mrs. X: "Phone me tomorrow afternoon."
from direct into indirect speech. My answer was
Mrs X. told her to phone her the afternoon of the following day.
Best Answer
No, there's nothing grammatically wrong with call him the morning of the next day. Arguably, it's semantically ambiguous (as in the old joke 'Call me a taxi.' All right, you're a taxi.') but in reality people accept this to avoid cumbersome phrasing; as Charles said, a native speaker would say call him the next morning. The further away the date is, the more likely it is that on will be used: call me tomorrow (not *on tomorrow), call me the next day or on the next day, but call me on Thursday (?Call me Thursday is used, but is informal).