その機械がなぜ動かないのかわかった。

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...

machine; mechanism; instrument; appliance; apparatus

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

why; how

to move; to stir; to shift; to shake; to swing; to operate; to run; to go; to work; to be touched; to be influenced; to change; to vary; to fluctuate; to waver; certain; factual; to be transferred

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

indicates a question (sometimes rhetorical); or; whether or not; some- (e.g. something, someone); indicates doubt, uncertainty, etc.; emphatic prefix; suffix forming adjectives or adverbs; in that way

to understand; to comprehend; to grasp; to see; to get; to follow; to become clear; to be known; to be discovered; to be realized; to be realised; to be found out