chores: update some wording

BEPs/BEP-520.md

@@ -89,11 +89,11 @@ func (p *Parlia) isBlockDelayMinedOnPurpose(header, parent *types.Header) {
 ```
 
 ### 4.2 Parameter Changes
-As mentioned above, phase one and phase two are highly relevant, their parameter changes will be put in one table for easy comparison.
+As mentioned above, phase one and phase two are highly relevant, their parameter changes will be put in one table for easy comparison. But the parameters of phase two here is only for reference, as it could be changed in the future when phase two is finally delivered.
 
 #### 4.2.1 Change table
 A multitude of system parameters are configured based on the assumption that the default block interval is 3 seconds. Consequently, when the block interval is altered, these parameters must be adjusted accordingly:
-|parameter |type |current value  | phase one(1.5s) | phase two(0.75s)|
+|parameter |type |origin(3s)  | phase one(1.5s) | phase two(0.75s)|
 |--------|--------|--------|--------|--------|
 |Epoch  |client parameter |200  |1000 |2000|
 |GasLimit |client parameter |140M |60M |30M|
@@ -146,10 +146,10 @@ The [Quarterly Auto-Burn](https://www.bnbburn.info/) mechanism also requires adj
 where T represents the number of seconds in the corresponding quarter.
 
 ### 6.4 Block Finality
-This BEP will not change the fast finality mechanism, but short block interval could bring challenges fast finality, as votes need to be propagated in a shorter time. When fast finality works properly, after this BEP, the average transaction finality time would be reduced from 7.5 seconds to 3.75 seconds.
+This BEP will not change the fast finality mechanism, but short block interval could bring some challenges to fast finality, as votes need to be propagated in a shorter time. When fast finality works properly, with this BEP, the average transaction finality time would be reduced from 7.5 seconds to 3.75 seconds.
 But if fast finality failed, with TurnLength 16 and ValidatorSize 21, for natural block finality, it will be:
-- (>1/2 validator confirm):  176(11*16) blocks, that is 264 seconds
-- (>2/3 validator confirm):  240(15*16) blocks, that is 360 seconds
+- (with >1/2 validator confirmations):  176(11*16) blocks, that is 264 seconds
+- (with >2/3 validator confirmations):  240(15*16) blocks, that is 360 seconds
 
 ## 7. License
 The content is licensed under [CC0](https://creativecommons.org/publicdomain/zero/1.0/).