3.a fly in the ointment使人扫兴的人(或事物)；煞风景的人(或事物)
If there is a fly in the ointment, it is that the engine is quite noisy.如果说有什么美中不足之处, 那就是发动机的噪音很大。
There is one small fly in the ointment.有一个小小的美中不足之处。
The fly in the ointment is debt of $485.7 million.煞风景的是那48,570万美元的债务。