-----the morning of Sptember 10th,we are going to give our teacher some flowers.
问题描述：
-----the morning of Sptember 10th,we are going to give our teacher some flowers.
A.On B.In C.At D./
答
无论是涉及到某一天,还是某一天的某个时候,都用介词on,选择A.On