阅读下面短文，在空白处填入一个适当的词，或填入括号中所给单词的正确形式。

    In recent years,sandstorms ____(occur) in China frequently,especially in northwestern areas, ____severe influence has caused wide concern in China.

There're several reasons for this.First of all,people are cutting down trees without planting more, ____(make) some land become deserts.Another reason is ____it rains less due to the environment pollution.

    To ____(efficient) prevent sandstorms,first,we should plant more trees and grass which can keep the soil ____ being washed away.Second,more green fences should ____(build) along the desert, ____it helps to control the process of the desertification.

    Let's take action to do what we can ____(prevent) sandstorms from today.Soon the golden days we have been looking forward to ____(come).

写出所给的单词。

① morning ____   

② afternoon ____     

③ evening ____    

④ night ____    

生物活动小组为了探究玉米的光合作用，设计了甲图所示三个装置，其中玉米幼苗、培养液、隔板、光照等条件都相同，请回答问题．