一、一般說(shuō)“在下午”的時(shí)候，要用in the afternoon

He's arriving in the afternoon.

他將于下午到達(dá)。

《柯林斯英漢雙解大詞典》

但是要說(shuō)具體某一天的下午，要用on the afternoon，后面通常會(huì)有of

例句1：I was at home on the afternoon of last Monday.

上個(gè)星期一的下午我在家。

例句2：Where were you on the afternoon of May 21?

5月21日下午你在哪里？

《牛津詞典》

二、morning和evening也是一樣的用法

1.in the morning：在早上

I can't get out of the habit of waking at six in the morning.

我早上六點(diǎn)鐘醒的習(xí)慣改不了。

《牛津詞典》

2.on the morning of：在具體某一天的早上

We got the news on the morning of the wedding.

我們?cè)谂e行婚禮的那天上午得到這個(gè)消息。

《牛津詞典》

3.in the evening：在晚上

I usually watch TV in the evening.

我通常晚上看電視。

4.on the evening of：在具體某一天的晚上

On the evening of my 14th birthday,I was given this book.

14歲生日的那天晚上我收到了那本書(shū)。