【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】_____ remains unknown to all.
A.
Why John committed suicide
B.
Why did John commit suicide
C.
Whom committed suicide
D.
When John did commit suicide
【多选题】导游在处理与境外旅游团领队的关系时,要()