diff --git a/OpenQuant.API/BarSeries.cs b/OpenQuant.API/BarSeries.cs
index a9ab8e6..5ed6b00 100644
--- a/OpenQuant.API/BarSeries.cs
+++ b/OpenQuant.API/BarSeries.cs
@@ -246,7 +246,7 @@ public BarSeries GetRange(DateTime dateTime1, DateTime dateTime2)
 		{
 			BarSeries barSeries = new BarSeries();
 			int index = this.series.GetIndex(dateTime1, EIndexOption.Next);
-			int index2 = this.series.GetIndex(dateTime1, EIndexOption.Prev);
+			int index2 = this.series.GetIndex(dateTime2, EIndexOption.Prev);
 			if (index != -1 && index2 != -1)
 			{
 				for (int i = index; i <= index2; i++)
diff --git a/OpenQuant.API/TimeSeries.cs b/OpenQuant.API/TimeSeries.cs
index ae90cb6..02dfed8 100644
--- a/OpenQuant.API/TimeSeries.cs
+++ b/OpenQuant.API/TimeSeries.cs
@@ -312,17 +312,49 @@ public double GetVariance(DateTime dateTime1, DateTime dateTime2)
 		{
 			return new TimeSeries(series1.series + series2.series);
 		}
+		public static TimeSeries operator +(TimeSeries series, double value)
+		{
+			return new TimeSeries(series.series + value);
+		}
+		public static TimeSeries operator +(double value, TimeSeries series)
+		{
+			return new TimeSeries(value + series.series);
+		}
 		public static TimeSeries operator -(TimeSeries series1, TimeSeries series2)
 		{
 			return new TimeSeries(series1.series - series2.series);
 		}
+		public static TimeSeries operator -(TimeSeries series, double value)
+		{
+			return new TimeSeries(series.series - value);
+		}
+		public static TimeSeries operator -(double value, TimeSeries series)
+		{
+			return new TimeSeries(value - series.series);
+		}
 		public static TimeSeries operator *(TimeSeries series1, TimeSeries series2)
 		{
 			return new TimeSeries(series1.series * series2.series);
 		}
+		public static TimeSeries operator *(TimeSeries series, double value)
+		{
+			return new TimeSeries(series.series * value);
+		}
+		public static TimeSeries operator *(double value, TimeSeries series)
+		{
+			return new TimeSeries(value * series.series);
+		}
 		public static TimeSeries operator /(TimeSeries series1, TimeSeries series2)
 		{
 			return new TimeSeries(series1.series + series2.series);
 		}
+		public static TimeSeries operator /(TimeSeries series, double value)
+		{
+			return new TimeSeries(series.series / value);
+		}
+		public static TimeSeries operator /(double value, TimeSeries series)
+		{
+			return new TimeSeries(value / series.series);
+		}
 	}
 }
diff --git a/README.md b/README.md
index 4dcfaef..67d361f 100644
--- a/README.md
+++ b/README.md
@@ -3,11 +3,20 @@ OpenQuant.API加强版
 
 此OpenQuant.API.dll是由ILSpy反编译后，经过部分修改，用Visual Studio重新编译而成。
 
-针对OpenQuant 3.9.2版本（会在OpenQuant新版本出来后跟进合并，OpenQuant 2014除外），x32/x64可通用。
+随时跟进OpenQuant最新版本，OpenQuant 2014除外，x32/x64可通用。
 
 ## Features
 
-1. 增加Bar constructor：`Bar(DateTime dateTime, double open, double high, double low, double close, long volume, long openInt, long size)`
+* 增加Bar constructor：`Bar(DateTime dateTime, double open, double high, double low, double close, long volume, long openInt, long size)`
+
+* 增加BarSeries的Crosses系重载函数：
+    - `Cross Crosses(double level, Bar bar)`
+    - `bool CrossesAbove(double level, Bar bar)`
+    - `bool CrossesBelow(double level, Bar bar)`
+
+* 为BarSeries和Indicator增加Implicit Conversion Operator，分别转换为BarSeries.Last.Close和Indicator.Last，支持如`indicator + bars * 0.001`等语句；
+
+* 增加TimeSeries的加减乘除运算符重载，支持`timeseries + 42`或`42 + timeseries`运算，返回TimeSeries类型。
 
 ## Developer's Guide