某中学生按正常速度步行4km,所需时间大约是( )
A:40s
B:8min
C:1h
D:4h
在数列an中,a1=2, an+1=an+ln(1+1n),则an= ( )
Let's ask the teacher for help. She ________ the answer.
古人云:“君子和而不同,小人同而不和 ”这表明 ( )