I fancy that I heard a noise.
Monooto ga kikoeta yō da.
indicates sentence subject (occasionally object); indicates possessive (esp. in literary expressions); but; however; still; and
to be heard; to be audible; to be said to be; to be reputed
appearing ...; looking ...; way to ...; method of ...ing; form; style; design; like; similar to; thing (thought or spoken)
be; is; indicates past or completed action; indicates light imperative