如图是苹果树栽培生产中常用的操作步骤示意图，①为苹果树的枝条，②为海棠的树根，请根据图回答：
—What about _____ English-Chinese dictionary on the bookshelf?—In my opinion, it's _____ useful tool book for my English learning.
热带和温带的分界线是（ ）
