（白杨）是六年制小学语文第九册的一篇讲读课文。写一位在新疆工作的父亲，在通往西北的一列火车上向自己的子女介绍戈壁滩上白杨的特点，借以表达自己扎根边疆、建设边疆的志向，同时教育子女要像白杨那样，在边疆生根、发芽、成长。这一中心思想，是教学的重点；课文内容含? (Poplar) is a lecture text of the ninth volume of six-year primary Chinese. Write a father who works in Xinjiang to introduce his own children to the characteristics of poplar on the Gobi Desert on a train to the northwest in order to express his aspirations to take root in the frontier and build the frontier while educating their children to be as poplar-like, at the frontier Rooting, germination, growth. This central idea is the focus of teaching; text content contains?