その少年はポケットに手を入れた。

that (something or someone distant from the speaker, close to the listener; actions of the listener, or ideas expressed or understood by the listener); the; um...; er...; uh...

boy; juvenile; young boy; youth; lad

topic marker particle; indicates contrast with another option (stated or unstated); adds emphasis

pocket

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

hand; arm; forepaw; foreleg; handle; hand; worker; help; trouble; care; effort; means; way; trick; move; technique; workmanship; hand; handwriting; kind; type; sort; one's hands; one's possession; ability to cope; hand (of cards); direction; move (in go, shogi, etc.)

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