Green circles in the desert frequently indicate tracts of agriculture supported by centre-pivot irrigation.
这片位于沙漠里的密集绿圈代表由中枢灌溉系统支持的农业生产。
2
Screen Angle indicator: a protractor with many co - centrecircles.
网角指示器：是一个带有很多同心圆的量角器。
3
The three circles that Wang Mingming has suggested can be considered as circles of Chinese civilisation and the world system in which it is a major centre.