☆「in the morning」
I usually have meetings in the morning.
the morningの前につく前置詞は後ろに引っ張られる。
☆「on the morning ＋ of the ＋ 日付（序数）」
I’ll have a meeting on the morning of the 15th.
☆「on the morning ＋ of ＋ 月 ＋ 日付（序数）」
I’ll have a meeting on the morning of June 15th.
☆「on ＋ 曜日 ＋ morning」
I’ll have a meeting on Monday morning.