Mike
saw a film
John
cleaned the room
Wu Yifan
had a cold
Chen Jie
read a book
Zhang Peng
went fishing
下列四个盆地中,位于湿润地区的是( )
按图示的规律搭下去,则所用火柴棒数an 与所搭三角形的个数n之间的关系式可以是____.