add more comments

Author: gh-yzou

LogicalTypes.md

@@ -550,9 +550,9 @@ are found during reading, they must be ignored.
 `4 years and 6 months`. It must annotate an `int32` that stores the total number
 of months as a signed integer, which represents the interval and can be negative.
 
-While ANSI SQL systems typically restrict supported intervals to a range of ±10,000 years 
-and enforce this constraint internally, the Parquet format does not impose 
-any limitations on the interval values that may be stored.
+While ANSI SQL systems typically restrict supported intervals to a range of 
+±10,000 years and enforce this constraint internally, the Parquet format 
+does not impose any limitations on the interval values that may be stored.
 
 #### DURATION
 
@@ -564,10 +564,9 @@ duration. The duration is purely a measure of time and is independent of any tim
 The `DURATION` type takes `unit` as a parameter, and the value must be one of
 `MILLIS`, `MICROS` or  `NANOS`.
 
-`Duration` can be used to represent DayTime Intervals as defined by ANSI SQL. In this
-context, a duration of 1 day is strictly defined as 24 hours, regardless of the actual 
-number of hours in a calendar day. For example, a 1-day duration is always equal to 
-86,400,000,000 nanoseconds.
+`Duration` can be used to represent DayTime Intervals as defined by ANSI SQL. In 
+this context, a duration of 1 day is strictly defined as 24 hours, regardless of 
+the actual number of hours in a calendar day. 
 
 ## Embedded Types