Money down the drain:
If money is or goes down the drain, it is spoiled or wasted.
字面意思是 “钱流进下水道”，实际意思是 “花在某件事情上的钱被白白浪费，白花钱”。如果想表示 “把钱打水漂”，则可以说 “throw money down the drain”。
例句
Trying to heat our house is money down the drain – the heat just escapes through the windows!
我们设法为房子供暖，但就是白花钱，因为热气都从窗户缝里漏出去了！
Buying this second-hand bike was money down the drain – I had to spend so much on getting it repaired!
买这辆二手自行车真是白花钱了，因为我又花了很多钱去修理它！
Building a new car park in the town is money down the drain – there are three other car parks already.
在镇上建一个新的停车场就是在浪费钱，因为已经有三个停车场了。
