If there no buying and selling of animals, there no killing in nature.
A:is; will be
B:will be; will be
C:is; is
D:will be; is
实验是进行科学探究的重要方式,某同学设计如图所示实验,探究二氧化碳的有关性质.请填空:
Stop cutting trees, _______ the earth will become worse and worse.
下列属于意识能动性的有( )