A:just; already
B:yet; never
C:yet; already
D:already; yet
- I don't think students should use mobile phones at school.
- ______. They really have a bad influence on our study.
小明为了证明蚯蚓喜欢阴暗的环境,他选择了两条蚯蚓,一条放在光下,另一条放在阴暗处。他的行为属于( )