Helen has picked up French and can speak fluently after a short stay with her aunt in Paris.
A:捡起,拾起
B:开车接某人
C:接收,收听
D:偶然学会
- When will our guests arrive at the airport?
- __________ the evening of this Saturday.
在三棱锥P-ABC中,PA=PB=PC,底面△ABC是正三角形,M、N分别是侧棱PB、PC的中点.若平面AMN⊥平面PBC,则平面AMN与平面ABC所成二面角(锐角)的余弦值等于( )
图是晓丽从生活中收集到的一些光现象的实例,以下说法正确的是