fixup!

book/src/read-only-read-write-accounts.md

@@ -127,9 +127,9 @@ transactions are processed.
 
 The downside with this approach is that if the `lock` set mutex is released
 between lock and load to allow better pipelining of transactions, a request for
-a read-only account may fail, so this design is not suitable for treating
-programs as read-only accounts.
+a read-only account may fail. Therefore this approach is not suitable for
+treating programs as read-only accounts.
 
-Holding the accounts lock mutex would potentially have a significant performance
-hit on the runtime. Fetching from disk is expected to be slow, but can be
-paralyzed between multiple disks.
+Holding the accounts lock mutex while fetching the Account from disk would
+potentially have a significant performance hit on the runtime. Fetching from
+disk is expected to be slow, but can be parallelized between multiple disks.