You won't want to visit any other mountain if you have seen Wu yue, but you won't wish to see even Wu yue _______returning from Mount Huangshan.
A:about
B:before
C:since
D:after
鉴别空气、氧气和二氧化碳三瓶气体,最佳的做法是( )
下列变化不属于化学变化的是( )
将大鼠生长激素基因用显微注射的方法,转入小鼠的受精卵中,再移植到小鼠体内发育,生出的小鼠比普通小鼠的生长速度快2~3倍.该实验不能够说明的是( )