or: If we want arrive at ten, I don't think it's necessary to start /set out/ set off so early.
or: I don't think it's necessa
欧洲流经国家最多的河流是( )
下图是测定植物某一生命活动过程的装置,从左侧泵入空气后,会产生某些实验现象,下列几种说法中错误的是: