"A white elephant" means something that is useless, although it may cost a lot of money.

“白象”指的是无用却很昂贵的东西。

youdao

Its sister ship the Kuznetsov survived, but by the time the Soviet Union ceased to exist, the Varyag was a white elephant marooned off a port in the Black Sea.

它的姐妹舰库兹涅佐夫仍在服役，不过当前苏联分崩离析之时，瓦良格号这一白色的庞然大物却漂泊在黑海一港口之外。

youdao

Host a White Elephant Exchange, in which friends and family bring unwanted gifts and all take turns pulling a number out of a hat to pick the next bizarre present.

举办一场无用的礼物交换活动。突施妙计让你的朋友或家人把他们不中意的礼物换成另一件不寻常的。

youdao

Much, then, is riding on the success of a plane that Boeing dismisses as a white elephant.

ECONOMIST: The biggest shareholders in EADS are preparing to sell up

They point out the "ghost town" of Kilamba in Angola, a grandiose project often labeled as a white elephant.

CNN: Africa's 'new cities': Urban future or utopian fantasies?

There will be endless promises to ensure that there is a positive legacy of London 2012, that we are more sporting as a nation, more inclusive and that the Olympic Park revives east London and does not become a white elephant.

BBC: Boris and the Olympic legacy made flesh