update descriptions of regenerate output

Author: likebupt

articles/machine-learning/algorithm-module-reference/export-data.md

@@ -36,11 +36,11 @@ Before exporting your data, you need to first register a datastore in your Azure
 
 1. For **Datastore**, select an existing datastore from the dropdown list. You can also create a new datastore. Check how by visiting [Access data in Azure storage services](../how-to-access-data.md).
 
-1. The checkbox, **Regenerate output**, decides whether execute the module with rewriting results each time. The checkbox is by default unselected, to save resource.
+1. The checkbox, **Regenerate output**, decides whether to execute the module to regenerate output at running time. 
 
-If you select this option, results are written to storage each time the module is run, regardless of whether the output data has changed.
+    It's by default unselected, which means if the module has been executed with the same parameters previously, the system will reuse the output from last run to reduce run time. 
 
-If you deselect this option, Export Data uses cached data, if available. New results are generated only when there is an upstream change that would affect the results.
+    If it is selected, the system will execute the module again to regenerate output.
 
 1. Define the path in the datastore where the data is. The path is a relative path. The empty paths or a URL paths are not allowed.
 

articles/machine-learning/algorithm-module-reference/import-data.md

@@ -54,11 +54,12 @@ If your source data changes, you can refresh the dataset and add new data by rer
 
     ![import-data-preview](media/module/import-data.png)
 
-1. The checkbox, **Regenerate output**, decides whether execute the module with rewriting results each time. The checkbox is by default unselected, to save resource.
+1. The checkbox, **Regenerate output**, decides whether to execute the module to regenerate output at running time. 
 
-If you select this option, results are written to storage each time the module is run, regardless of whether the output data has changed.
+    It's by default unselected, which means if the module has been executed with the same parameters previously, the system will reuse the output from last run to reduce run time. 
+
+    If it is selected, the system will execute the module again to regenerate output. So select this option when underlying data in storage is updated, it can help to get the latest data.
 
-If you deselect this option, Import Data uses cached data, if available. New results are generated only when there is an upstream change that would affect the results.
 
 1. Run the pipeline.