A．Similarly B．popular C．focus D．within E. Importantly
Primary school students are being offered a unique choice to school education at The Nature School in New South Wales.
Half of the school day is spent outdoors learning subjects such as English, maths and science with a 21． on independent thinking, The students enjoy a full outdoor adventure day once a week while outdoor play also takes place every day, whatever the weather.
The concept was first from Europe, where, "forest schools" have been 22． for more than ten years. The philosophy is about children learning from and 23． nature. For example, walking around the bush with a clipboard allows for writing and drawing. 24．, a maths lesson on weight, mass or length can take place in the natural environment.
21．focus
22．popular
23．within
24．Similarly
【解析】
本文是一篇说明文。文章主要讲述新南威尔士州的小学为学生教育提供了独一无二的选择。以及讲述自然学派的理论在课堂中的运用。
21．句意：（学生有）半天时间是在户外度过的，学习英语、数学和科学这些科目，注重独立思考能力。
根据句意以及横线前的a提示填名词，后面on提示用focus，a focus on关注于……，聚焦于……。故答案为focus。
22．句意：这个概念起源于欧洲，“森林学校”已经在那里流行了十多年。
横线处前有be动词，可知此处填形容词词性单词，根据句意以及所给单词可知，此空用popular流行的。故答案为popular。
23．句意：此哲学观点说的是儿童向自然学习，在自然中学习。
根据前文learning from可知是向自然学习，and连接两个词性相等的词，from是介词，横线处也是介词，用within在……之内，learn within nature在自然中学习。故答案为within。
24．句意：类似地，也可以在自然环境中上一节关于重量、数量或长度的数学课。
根据前文例子“For example, walking around … and drawing”以及后文“a maths lesson …natural environment.”可知，学生可以在灌木丛中走动学习书写和画画，也可以在自然环境中上数学课，二者是类似的，所以用similarly，句首首字母大写。故答案为Similarly。