Not "Amina's birthday is at May." — say "Amina's birthday is in May.". 像月份这种较长的时间段要用 in，不是 "at"。
试一试: Amina's birthday is ___ May. (in / at / on) 答案: in — 月份用 in：in May。"at" 是用在具体钟点上的，不是月份。
on = 日期
记住这个搭配：on + 日期。日期就是月份加上几号：on May 3。
The art show is on June 6.
My class starts on September 10.
The party is on the twenty-first.
Not "The art show is in June 6." — say "The art show is on June 6.". 单说 June 要用 in，但 June 6 是日期，日期用 on。
试一试: Mateo: Write it in your book. The art show is ___ October 4. (on / in / at) 答案: on — October 4 是日期，也就是月份加几号，日期用 on。
at、on 还是 in？
这三个时间词分别对应三种大小的时间：
at + 钟点：at seven o'clock
on + 某一天或日期：on Monday, on May 3
in + 月份、季节或年份：in May, in winter, in 2024
The doors open at eight-thirty.
We have class on Tuesday.
Her birthday is in May.
Not "Her birthday is on May." — say "Her birthday is in May.". May 3 是日期，用 on；但单说 May 是月份，用 in。
试一试: The party is ___ Saturday. (on / in / at) 答案: on — Saturday 是某一天，所以用 on：on Saturday。
试一试: Lani: When do the new classes start? Farid: They start ___ September, right after the summer. 补全 Farid 的回答。 (in / on / at) 答案: in — Farid 说的是月份，没有几号，月份用 in。September 10 这样的日期要用 on，钟点要用 at。