Definition
This idiom indicates that something is acceptable or useful in some situations but not ideal or perfect in every situation.
尚可，但不太好
Picnics are all very well when the weather is nice, but they don't work when it rains.
野餐在天气好的时候是还不错，但下雨时就不行了。
The plan sounds all very well in theory, but it has encountered many problems in practice.
这个计划在理论上听起来不错，但在实践中遇到了很多问题。
Dieting is all very well, but it is very difficult to stick with for a long time.
节食是还不错，但很难长期坚持。