不思議なのは彼がそれを知っていたことだ。

wonder; miracle; strange; mystery; marvel; curiosity

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

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

he; him; his; boyfriend

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

that (indicating an item or person near the listener, the action of the listener, or something on their mind); it; that time; then; there (indicating a place near the listener); you

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 be aware of; to know; to be conscious of; to cognize; to cognise; to notice; to feel; to understand; to comprehend; to grasp; to remember; to be acquainted with (a procedure); to experience; to go through; to learn; to be acquainted with (a person); to get to know; to concern

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

be; is; indicates past or completed action; indicates light imperative