于【yú】

于 is the written preposition for place, time, comparison and target. Most often it comes straight after a verb or adjective, in the spot where speech would use 在, 比, 对 or 从 somewhere else in the sentence.

Place and time

Verb + 于 + place or time gives "in", "at", "on". Speech says the same with 在 or a time word before the verb: 他1990年出生. In notices and news, 于 + time can also stand before the verb.

Comparison after an adjective

Adjective + 于 + B means "more than B". It is the written cousin of 比 and works mainly with 大, 小, 高, 低, 多, 少: A 高于 B says the same as A 比 B 高.

The order is the opposite of 比: 于 follows the adjective.

• × 他于我高 → 他比我高 / 他高于我

Target or field

After some verbs and adjectives, 于 marks what something is aimed at or the area it concerns: 有利于 "good for", 善于 "good at", 忙于 "busy with", 来自于 "come from", 归功于 "owe to".

Too formal for conversation

In speech, 于 sounds like a document. Talking about your evening, use 在.

• × 我晚上七点于家吃饭 → 我晚上七点在家吃饭

由于, 关于, 对于, 终于, 等于 and 属于 contain 于 but are learned as words, and several have their own entries.