not only is experience the best teacher,but also we can lear

Not only is experience the best teacher,but also we can learn much things from failure
这样的表达,单从语法上看,好像没有问题.
不过,严格考察not only...but also 的用法,可知,它需要连接【对等成分】,即被连接的两部分在词性、结构形式和语用表达上,应该属于相同性质或近似性质的内容.
而所给句子中,【is experience the best teacher】和【we can learn much things from failure
】显然不属于对等结构.
如果你坚持使用此语义和结构,建议改为类似这样的形式：
Not only is experience the best teacher but also failure is the best friend who can give us a lot.
在你开心如意!O(∩_∩)O~~