名词 covert:

1. a flock of coots

2. a covering that serves to conceal or shelter something

covertadj.隐蔽的；偷偷摸摸的；隐密的n.掩蔽物；树丛；覆羽covert rules潜规则covert words潜词covert sense隐意covert fault隐性故障covert cloth斜纹大衣呢covert image掩密图像covert error隐性错误covert motive内隐动机covert threat潜在的威胁； 没暴露的危险迹象covert speech内隐言语

1. Usually there is a distinct contrast between the black primaries and brown coverts, still evident at middle distances.
   长尾水剃通常在黑色的初级飞羽与棕色的覆羽之间有著明显的对比，在中距离的时候仍是可见的。
2. Its tail is long and black with gray uppertail coverts and orange brown undertail coverts.
   尾羽修长黑色，尾上覆羽灰色，尾下覆羽橙褐色。