Chinese sayings :

此地无银三百两 (cǐ dì wú yín sān bǎi liǎng)
literally meaning : "there are no 300 silvers (buried) here"

Means, the silver is actually buried here, yet I tell you there are no silvers buried yet, is indirectly telling you YES there are silvers buried here
( for full meaning, look here )

1. 空中楼阁 (Castle in the air) kōng zhōng lóu gé

空 means the sky or the air. 中 is in the middle of. 楼 is a building, 阁 means a cabinet or chamber. So 空中楼阁 means the house built in the sky or a castle in the air. It's a way of criticizing someone's daydreams or impractical plans.

1. 对牛弹琴 (playing the lute/qin(musical instrument) for the cow) duì niú tán qín

对duì means face to; 牛niú is the cow. 弹tán means to play, and 琴qín is the musical instrument. It usually implies that someone speaks or writes without considering his audience. He tries to explain deep truths to a dull person or speaks elegantly and far above the listener's understanding. More often than not, the speaker or writer has over-estimated his listeners or readers. In these cases, the idiom chastises the audience rather than the speaker.