Learn Hardcore Japanese: sigoto no ato, hana wo butyou ni okutta. - After work, I sent flowers to the department manager.

の links the noun 仕事 (“work”) to あと (“after”), so the combined phrase literally means “the after of work,” i.e. “after work.” It’s a common way to turn one noun into a descriptor for another.

Why doesn’t the sentence say 仕事が終わったあと instead of 仕事のあと? Are they interchangeable?

They’re both correct, but 仕事のあと is shorter and more colloquial. 仕事が終わったあと explicitly uses the verb 終わる (“to finish”) to mean “after work finishes.” In everyday speech, dropping the verb and saying 仕事のあと is perfectly natural.

What does the を particle do in 花を送った?

を marks 花 (“flowers”) as the direct object of the verb 送った (“sent”). In English, it corresponds to the object marker — “I sent flowers.”

Why is 部長 followed by に in 部長に送った?

に indicates the recipient of an action. Here, 部長に送った means “sent to the manager.” Whenever you give, send, or show something to someone, that person is marked with に.

Why is there no subject (like “私は”) in this sentence?

Japanese often omits the subject when it’s clear from context. If you’re talking about your own action, you can drop 私は. The listener understands “I” sent the flowers.

What tense and politeness level is 送った, and how would I make it more polite?

送った is the plain past form (“I sent”). To make it polite, use 送りました. So a more formal version would be 仕事のあと、花を部長に送りました。

Could we say お花 instead of 花? What difference does the お make?

Yes. Adding お (making it お花) adds a polite or honorific nuance, showing respect or delicacy toward the object. It’s common when giving or mentioning gifts like flowers.

Why isn’t 部長 followed by さん, like 部長さん?

When using job titles as direct forms of address or reference (部長, 先生, 社長, etc.), Japanese typically omits さん. Saying 部長 is already polite and clear as “the department manager.”