按规律填数:15,12,9,______.
15-12=3,12-9=3,所以后面应填:9-3=6.
故答案为:6.
three times,but she still couldn’t follow what the old man said.
A.Having told
B.Having been told
C.She had been told
D.Though he had been told
在电解水的实验中,若与电源正极相连的试管内收集了nL气体,则与电源负极相连的试管内理论上可以收集到的气体的体积为 [ ]
A、nL
B、2nL
C、0.5nL
D、0.8nL