纵断面高于水平线时取正值,低于水平线的面积取负值。The vertical section is positive when it is higher than the horizontal line, and the area below the horizontal line is negative.
【简答题】【 2017 下 初 中 】 教学情境分析题:( 30 分) 根据题目要求完成下列任务,用中文作答。 下面是一位初中英语教师在语音教学中使用的练习。 Teacher's instruction: Look at the words on the blackboard. Tick the word you hear in each sentence I read. Teacher's reads: ...