常见例句The origin of the mysticete's low-frequency hearing is far murkier, even though the fossil evidence of that group now dates back to as early as 34 million years ago. 雖然就化石記錄來看，須鯨在3400萬年前（漸新世初期）就出現了，可是牠們的低頻聽覺起源仍然混沌不明。 返回 mysticete