Which two statements are correct about Nonstop Forwarding？（）
A. It allows the standby RP to take control of the device after a hardware or software fault on the active R
B. It is a Layer 3 function that works with SSO to minimize the amount of time a network is unavailable tousers following a switchover.
C. It is supported by the implementation of EIGRP， OSPF， RIPv2， and BGP protocols.
D. It synchronizes startup configuration， startup variables， and running configuration.
E. The main objective of NSF is to continue forwarding IP packets following a switchover.
F. Layer 2 802.1w or 802.1s must be used， as 802.1d cannot process the Layer 2 changes.
G. Routing protocol tuning parameters must be the same as the NSF parameters， or failover will beinconsistent.
对于M7120型磨床的液压泵电动机和砂轮升降电动机的正反转控制采用（）来实现。
A. 点动
B. 点动互锁
C. 自锁
D. 互锁
《素问·阴阳应象大论》曰：“能知七损八益，则二者可调。”“二者”是指（）
A. 气血
B. 脏腑
C. 阴阳
D. 表里
E. 虚实
支承某曲柄的两个主轴承低于其他轴承，△垂直>O时，则该曲轴轴线呈（）状态。
A. 拱腰形
B. 塌腰形
C. 左拱形
D. 右拱形
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