【单选题】What are they doing ?
A.
They are taking photos.
B.
They are shooting films.
【单选题】下列各组物质中互为同系物的一组是
B.
CH =CH-CH 和CH =CH-CH -CH
【单选题】下列物质中与CH3OH互为同系物的是( )
【单选题】what are they doing ?
A.
They are taking photos.
B.
They are cutting or editing films.
【单选题】What are they doing?
A.
they are taking photos
B.
they are cutting or editing films