A:was the mountain climber rescued
B:that the mountain climber was rescued
C:when the mountain climber was rescued
D:then the mountain climber was rescued
斯大林曾经说:“这次行动按其计划的周密,规模的宏大和行动的技巧来说,在战争史上还从来没有过类似的先例。它迫使纳粹德国在两个战场上同时作战”。斯大林所说的“这次行动”指的是( )
下列对空气的描述不正确的是( )
如图是利用天竺葵探究“绿叶在光下制造淀粉”的实验操作示意图,请回答下列问题: