我認為我知道是誰做的。

to make; to produce
to write; to compose
to do; to engage in; to hold (a party etc)
(of a person) to be (an intermediary, a good student etc); to become (husband and wife, friends etc)
(of a thing) to serve as; to be used for
to assume (an air or manner)

of; ~'s (possessive particle)
(used after an attribute when it modifies a noun)
(used at the end of a declarative sentence for emphasis)
(used after a noun, verb or adjective to form a nominal expression, as in 皮革的 pígéde "one made of leather" or 跑堂儿的 pǎotángrde "a waiter (literally, one who runs back and forth in a restaurant)" or 新的 xīnde "new one")
also pr. dì or di in poetry and songs