1、Stupid指“智力差的”、“反应迟钝的”.例如：
Mary made a stupid mistake.玛丽犯了一个笨拙的错误.
He is very stupid in learning maths.他学数学很笨.
Henry is too stupid to understand such a complicated problem.
亨利太笨了,他不理解这么复杂的问题.
2、Silly指“头脑简单瓣、不懂事的”、“傻头傻脑的”.例如：
Don’t be silly!别傻!
Stop asking such silly questions!别再问这样傻的问题了!
It was silly of you (You were silly)to trust him.你真傻竟相信了他.
概括起来,stupid相当于“笨”,silly相当于“傻”.