A grey area 灰色地带
The Empire State Building opened during the Great Depression in 1931 and was the tallest in the world until 1972 when the World Trade Center was finished. The structure is perhaps best known for being climbed by a huge ape in the 1933 movie version of "King Kong".
英语中的 a grey area 意思是灰色地带或没有明确正误答案的、含糊不清的一个问题。
When it comes to the law there are many grey areas.
The difference between flirting and harassment is a grey area.
另一个短语 shades of grey 有类似意思，通常在正误界定不清的时候使用。
Many children's stories say the world is full of black and white choices. In reality there are many shades of grey.