update tools

Signed-off-by: NTing Wang <kathy.wangting@huawei.com>

lite/tutorials/source_en/use/benchmark_tool.md

@@ -16,7 +16,7 @@
 
 ## Overview
 
-The Benchmark tool is used to perform benchmark testing on a MindSpore Lite model. It can not only perform quantitative analysis (performance) on the forward inference execution duration of a MindSpore Lite model, but also perform comparative error analysis (accuracy) based on the output of the specified model.
+After model conversion and before inference, you can use the Benchmark tool to perform benchmark testing on a MindSpore Lite model. It can not only perform quantitative analysis (performance) on the forward inference execution duration of a MindSpore Lite model, but also perform comparative error analysis (accuracy) based on the output of the specified model.
 
 ## Environment Preparation
 

lite/tutorials/source_en/use/timeprofiler_tool.md

@@ -14,7 +14,7 @@
 
 ## Overview
 
-The TimeProfiler tool can be used to analyze the time consumption of forward inference at the network layer of a MindSpore Lite model. The analysis is implemented using the C++ language.
+After model conversion and before inference, you can use the TimeProfiler tool to analyze the time consumption of forward inference at the network layer of a MindSpore Lite model. The analysis is implemented using the C++ language.
 
 ## Environment Preparation
 

lite/tutorials/source_zh_cn/use/benchmark_tool.md

@@ -16,7 +16,7 @@
 
 ## 概述
 
-Benchmark工具是一款可以对MindSpore Lite模型进行基准测试的工具。它不仅可以对MindSpore Lite模型前向推理执行耗时进行定量分析（性能），还可以通过指定模型输出进行可对比的误差分析（精度）。
+转换模型后执行推理前，你可以使用Benchmark工具对MindSpore Lite模型进行基准测试。它不仅可以对MindSpore Lite模型前向推理执行耗时进行定量分析（性能），还可以通过指定模型输出进行可对比的误差分析（精度）。
 
 ## 环境准备
 

lite/tutorials/source_zh_cn/use/timeprofiler_tool.md

@@ -14,7 +14,7 @@
 
 ## 概述
 
-TimeProfiler工具可以对MindSpore Lite模型网络层的前向推理进行耗时分析，由C++语言编码实现。
+转换模型后执行推理前，你可以使用TimeProfiler工具对MindSpore Lite模型网络层的前向推理进行耗时分析，它由C++语言编码实现。
 
 ## 环境准备