婷婷丁香久久,日日夜夜天天久久,中文av岛国无码免费播放,国产最新进精品视频,一进一出下面喷白浆视频,天天夜夜人人,97免费在线观看视频

Xinhua pictures of the year 2018

Source: Xinhua| 2019-01-05 16:57:04|Editor: Liangyu
Video PlayerClose

XINHUA-PICTURES OF THE YEAR 2018

Researchers check the surface of a four-meter-aperture optical mirror developed by Changchun Institute of Optics, Fine Mechanics, and Physics of the Chinese Academy of Sciences in Changchun, northeast China's Jilin Province, Aug. 21, 2018. China has developed a high accuracy four-meter-aperture optical mirror, an important tool for deep space and astronomical observation. (Xinhua/Xu Chang)

KEY WORDS: China
EXPLORE XINHUANET
010020070750000000000000011100001377218131