Nowadays, an increasing number of museums are open to visitors free. However, free ______ might lead to some social problems as well.
A:accommodation
B:attraction
C:admission
D:adjustment
下列山脉中,属于南北走向的一列是 ( )
我国的航母正按计划进行各项科研试验和训练,如图所示是中国航母“瓦良格”号训练时的图片,当飞机飞回航母后( )(注:航母的总重增加了)