安吉白茶茶园早春气温垂直分布特征明显，茶园昼夜温差大，逆温天气频繁出现，凌晨5：00左右逆温最强，风扇高度与茶园冠层的温差达到了4℃；霜冻天气来临时，防霜风扇（左图）对茶园增温效果明显，能有效预防消除茶园霜冻害.“为茶园某时气温垂直分布示意图”（右图），据此回答下列问题。
“防霜冻风扇”最适宜的安装高度为（）
A.9-10米
B.7-8米
C.6-7米
D.4米以下
参考答案：B
解析：
由右图可知通常情况下在4—8米之间随着高度的升高，气温升高，有逆温层存在，安装在7-8米之间有利于将高处的暖空气往下吹到茶树上，使茶树减轻或免受霜冻影响，故选项B正确。
任务型阅读 Our teacher work very hard. They get up early in the morning and work very late. How to help our teacher ? First, we must try to learn our subjects（科目）well to make our teachers spend less time on us and let them have more rest. Second, we must clean the blackboard and the teacher’s desk very often. If (如果) we can do so, our teachers will work better and of course they will be happier. Our teachers often have to speak for a long time and they are very thirsty(口渴的). At this time, it is better for us to bring them some water. When our teachers drink the water, they will speak more clearly (清楚). After our teachers correct (批改)our exercise books, we can help to hand them out (分发它们). If we do so, our teachers can have a short rest. We all know that our teachers care about our marks (关心我们的分数) most, so we should try to go over(复习) our lessons to get high grades（成绩）.If all of us can get high grades, our teachers will feel (感觉)very happy.
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