A:第一象限
B:第二象限
C:第三象限
D:第四象限
翘____(qiáo qiào)首 膝____(xī qī)盖 眷____(juàn quàn)恋
教诲____(huǐ huì) 烙____(lào luò)印 炽____(zhì chì)热
Mary didn't go to school yesterday. ____ ____ ____ she had a cold.
当光从水中斜射入空气中时,在分界面同时 发生反射和折射,反射角 ____入射角,折射角 ____入射角(以上两空选填“大于”、“等于”或“小于”),当入射角减小到0°时,折射角等于 ____