EIP-155 adds chain ID as a transaction signature parameter, but there is no guarantee that a PoW forked chain would adtop a different chain ID from mainnet.
If the chain ID is the same, transactions intended for mainnet or forked chain could be replayed on the other chain.
21/
EIP-155 添加链 ID 作为交易签名参数，但不能保证 PoW 分叉链会添加与主网不同的链 ID。
如果链 ID 相同，则用于主网或分叉链的交易可以在另一条链上重放。
21/