xiǎng / zài / yì / tiān / nèi / wán / chéng / zhè / me / dà / de / gōng / chéng / jiǎn / zhí / shì / shuǐ / zhōng / lāo / yuè

想在一天内完成这么大的工程，简直是水中捞月。

Trying to complete such a large project in one day is simply hopeless.