学习注释和#号，发音：hash ,octothorpe.
前面增加#就是注释,当然不能在引号内作为普通字符
倒着阅读代码的方法，可以避免大脑跟着代码走，可以查错
#A common ,this is so you can read your program later.
#Anything after the # is ignored by python.
print("I could have code like this.")# and the commond after is ignored
#you can also use a common to "disable" or common out code:
#print ("this won't run")
print("This will run.")