この道具は、不注意に使われると、とても危険なことがある。

this (something or someone close to the speaker (including the speaker), or ideas expressed by the speaker)

tool; implement; instrument; utensil; apparatus; device; means

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

carelessness; inattention; thoughtlessness

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

to use (a thing, method, etc.); to make use of; to put to use; to use (a person, animal, puppet, etc.); to employ; to handle; to manage; to manipulate; to use (time, money, etc.); to spend; to consume; to use (language); to speak

if; when; and; with; particle used for quoting (with speech, thoughts, etc.); quoting particle; promoted pawn; indicates question (sentence end)

very; awfully; exceedingly; (not) at all; by no means; simply (cannot)

danger; peril; hazard; risk

thing; matter; incident; occurrence; event; something serious; trouble; crisis; circumstances; situation; state of affairs; work; business; affair; after an inflectable word, creates a noun phrase indicating something the speaker does not feel close to; nominalizing suffix; pretending to ...; playing make-believe ...; alias; aka; nickname; alternative name; also known as

indicates sentence subject (occasionally object); indicates possessive (esp. in literary expressions); but; however; still; and

to be (usu. of inanimate objects); to exist; to live; to have; to be located; to be equipped with; to happen; to come about