カメラにフィルムを入れるのを忘れた。

camera

at (place, time); in; on; during; to (direction, state); toward; into; for (purpose); because of (reason); for; with; by; from; as (i.e. in the role of); per; in; for; a (e.g. "once a month"); and; in addition to; if; although

film

indicates direct object of action; indicates subject of causative expression; indicates an area traversed; indicates time (period) over which action takes place; indicates point of departure or separation of action; indicates object of desire, like, hate, etc.

to put in; to let in; to take in; to bring in; to insert; to set (a jewel, etc.); to ink in (e.g. a tattoo); to admit; to accept; to employ; to hire; to accept; to comply; to grant; to adopt (a policy, etc.); to take (advice, etc.); to listen to; to pay attention to; to include; to pay (one's rent, etc.); to cast (a vote); to make (tea, coffee, etc.); to turn on (a switch, etc.); to send (a fax); to call

indicates possessive; nominalizes verbs and adjectives; substitutes for "ga" in subordinate phrases; (at sentence-end, falling tone) indicates a confident conclusion; (at sentence-end) indicates emotional emphasis; (at sentence-end, rising tone) indicates question

to forget; to leave carelessly; to be forgetful of; to forget about; to forget (an article)