High school is an important time to learning strategies and improve your study techniques.这个英语句子应如何划分句子成分?

High school 主语
is 系动词
an...techniques表语
and的左右是并列的
但不知道learning和improve为什么形式不一致.句子是High school is an important time to learn learning strategies and improve your study techniques.那成分如何划分？该句是简单句、并列句、复合句？带有从句的都是复合句，这里带了两个定语从句。