题目

语篇填空 Located in a natural depression in Guizhou, China's Five-hundred-metre Aperture Spherical Radio Telescope, (know) as FAST, has identified six pulsars (脉冲星) after one year of trial operation. It is the first time Chinese scientists have discovered pulsars using a radio telescope independently developed by Chinese scientists, thus (open) a new era of Chinese original space discovery.It is truly encouraging for China to have achieved such results in just one year. Since the first pulsar (discover), over 2, 700 pulsars have been identified. But almost all of them are the scop5．下列实验操作说法正确的是（　　）选项实验操作现象与结论（或装置用途）A2mL 2% CuSO4中加4～6滴2% NaOH溶液，振荡后加入0.5mL X溶液，加热煮沸未出现砖红色沉淀，说明X不含有醛基B可以用于比较Fe3+、I2、Cl2的氧化性强弱C某溶液加入浓NaOH溶液加热，在试管口放一片湿润的红色石蕊试纸中试纸变蓝，说明NH3溶于水显碱性D用图所示装置分离沸点相差较大的互溶液体混合物A．AB．BC．CD．D