要把一个落后的农业的中国改变成为一个先进的工业化的中国，我们面前的工作是很艰苦的，我们的经验是很不够的。因此，必须善于学习。

In transforming a backward agricultural China into an advanced industrialized country, we are confronted with arduous tasks and our experience is far from adequate. So we must be good at learning.

句子结构为：In transforming A into B, we are confronted with sth and sth is far from adequate. So we must be good at learning

In transforming ...为介词短语作方面状语。