【多选题】导游在处理与境外旅游团领队的关系时,要( )
【单选题】According to Paragraph 2, what remains unknown is______.
A.
how plants receive and handle the signals from their neighbors
B.
why plants spread chemical information to their neighbors
C.
how many types of plants release compounds into the air
D.
whether plants send chemical warnings to their neighbors
【单选题】_______ caused the accident remains unknown.
【单选题】以下哪个品牌延伸属于产品种类延伸的品牌延伸 ( )
【多选题】导游在处理与境外旅游团领队的关系时,要()