如图所示是排球场的场地示意图，设排球场的总长为L，前场区的长度为 $\frac{L}{6}$ ，网高为h，在排球比赛中，对运动员的弹跳水平要求很高．如果运动员的弹跳水平不高，运动员的击球点的高度小于某个临界值H，那么无论水平击球的速度多大，排球不是触网就是越界．设某一次运动员站在前场区和后场区的交界处，正对网前竖直跳起垂直网将排球水平击出，关于该种情况下临界值H的大小，下列关系式正确的是（   ）

    During the summer holiday，Alice had a nice trip．First she took a plane from Changchun to Beijing．She went to the Great Wall．She was very tired．But she was  happy．She likes Beijing very much．Then she went to London by plane．She visited Big Ben，the clock tower．There were many museums in London．She learnt a lot there．People in London love eating fish and chips．She stayed in London for 5 days．Then she took a plane to Shanghai．Then she went to Changchun by plane．

根据短文，判断正误。

要求：1. 表达清楚，语句通顺，意思连贯；2. 要点须包括表格中的所有信息，可适当发挥；3. 词数：80词左右。

一战期间，中国民族资本主义经济经历了“短暂的春天”。该时期民族工业发展的表现有（    ）