diff --git a/README.md b/README.md
index d10762dc..9fa0f67a 100644
--- a/README.md
+++ b/README.md
@@ -1,22 +1,22 @@
 # PythonPlantsVsZombies
   A simple PlantsVsZombies game. <br>
   `It's only for personal learning and noncommercial use. If this game infringes the copyright, please let me know.`
-* implement plants: sunflower, peashooter, wallnut, snowpeashooter, cherrybomb, threepeashooter, chomper, puffshroom, potatomine, spikeweed, scaredyshroom, squash, scaredyshroom, jalapeno, sunShroom, iceShroom, hypnoShroom.
-* implement zombies: zombie, flagzombie, coneheadzombie, bucketheadzombie, newspaperzombie.
-* use json file to store level data (e.g.position and time of zombies, background info)
-* support to select plant cards at the beginning of the level
-* support day level, night level, moving card select level and wallnut bowling level
+* Implement plants: sunflower, peashooter, wallnut, snowpeashooter, cherrybomb, threepeashooter, chomper, puffshroom, potatomine, spikeweed, scaredyshroom, squash, scaredyshroom, jalapeno, sunShroom, iceShroom, hypnoShroom.
+* Implement zombies: zombie, flagzombie, coneheadzombie, bucketheadzombie, newspaperzombie.
+* Use json file to store level data (e.g.position and time of zombies, background info)
+* Support to select plant cards at the beginning of the level
+* Support day level, night level, moving card select level and wallnut bowling level
 
 # Requirement
-* Python 3.7 
+* Python 3.7 or above
 * Notice: python version 3.7 is advisable, but not required. For LINUX: if your Linux system has a preinstalled python 3+, it's ok to run this game. Updating to python 3.7 directly may break LINUX Mint.
-* Python-Pygame 1.9
+* Python-Pygame 1.9 or above
 
 # How To Start Game
 $ python main.py
 
 # How to Play
-* use mouse to collect sun, select the plant cards and seed the plant 
+* use left mouse button(LMB) to collect sun, select the plant cards and seed the plant 
 * you can set the start level by changing START_LEVEL_NUM value in source/constants.py
   * level 1 and 2：day level
   * level 3: night level