霸王龙是陆地上生存过的最大的肉食性动物。霸王龙在北美洲和亚洲被发现了。
最初的霸王龙是一个叫做 Alectorsaurs( 对不起，不知道这个专业词）的动物。 它带有了许多后期霸王龙所拥有的特征：短臂，大头和特殊的脚。 但比霸王龙小一些。 从那种恐龙之后，霸王龙似乎很快的成为了巨型恐龙里的一种 （这句话的英语有点不对）。 他们至少是12米长，拥有一个1。4米长的头。 但他们的前臂短的来连自己的嘴都摸不到。 谁也不知道这前臂是用来干什么的
As we know, Air pllution is bad for our health.We have very
serious air pollution around, became the main environment problems in
our city.Air pollution has seriously affected our lives.
In order
to protect the air environment in the city, to protect our health,We
must do the following.First of all,We can use clean fuel When we drive
or take the bus.Of course,We can also ride a bicycle to replace
them.Second,We have to plant more trees, let us more fresh air.Of
course, there are many ways to protect environment.
I believe, as long as we all work together,We'll have a clean their homes.
Dreams are successions of images, ideas, emotions, and sensations that occur involuntarily in the mind during certain stages of sleep.The content and purpose of dreams are not definitively understood, though they have been a topic of scientific speculation, as well as a subject of philosophical and religious interest, throughout recorded history. The scientific study of dreams is called oneirology.Dreams mainly occur in the rapid-eye movement (REM) stage of sleep—when brain activity is high and resembles that of being awake. REM sleep is revealed by continuous movements of the eyes during sleep. At times, dreams may occur during other stages of sleep. However, these dreams tend to be much less vivid or memorable.Dreams can last for a few seconds, or as long as twenty minutes. People are more likely to remember the dream if they are awakened during the REM phase. The average person has about 3 to 5 dreams per night, but some may have up to 7 dreams in one night. The dreams tend to last longer as the night progresses. During a full 8-hour night sleep, two hours of it is spent dreaming.
以下内容选自一本科普读物。
I. 既然血液是红色的，为什么静脉是蓝色的呢？
事实上，静脉并非蓝色的，而是更接近淡**。尽管在人体外的血液看起来是红的，但在皮肤浅表的静脉里，它更接近紫色，但又略显暗红。在皮肤深层，这些充血的静脉反射出的红色光线稍逊于周边的皮肤，反衬之下就呈蓝色了。
II. 哪个工作更忙，心脏还是大脑？
这要看你是忙于思考还是忙于运动。在运动时，心脏的工作强度足足是大脑的三倍，在人的一生中传输的血液足以装满一个超级油箱。但是，从长期来看，大脑很可能更忙，因为即使人坐着不动，大脑消耗的能量仍然是心脏消耗的两倍，因此它也需要四到五倍的血液来供应。
