THNET P2型M1远程监控记录单元不具备以下哪种特点（）
A.集中管理
B.实时监测
C.自动告警
D.自带锂电池
参考答案：D
根据句意用适当的介词填空。
1. I usually download some music ________ the Internet.
2. Mr Li likes to write novels ________ the computer.
3. Bruce doesn't have a computer ________ home.
4. I always do the housework ________ the weekend.
5. Tony sometimes writes ________ his friend.
车轮不平衡会产生什么危害？
