cropland conversion into forest的用法和樣例：
例句
- No entity or individual may designate suppliers of seeds or saplings for the parties restoring farmland to forest.
任何單位和個人不得為退耕還林者指定種苗供應商。 - The program of the converting farmland into forest is a big systems engineering,which involes broad converage, invests much money and has high participation of farmers.
退耕還林是一項龐大的系統工程，覆蓋面廣，投資多，農民參與程度高。
