（合成寫作）
Reading講一個explosion，說這個explosion不是由asteroid 掉下來引起的. 舉了三點(diǎn):
A.2 周爆炸后去找particle是可以找到了。(某explosion的例子，reading中用來doubt和compare)但是Tunskga explosion 后19年人們才去search.，那么particles很有可能被河水和融化的冰沖走。另外，發(fā)現(xiàn)當(dāng)時河上的確是有ice的。所以可能性更大。
B.如果asteroid explosion 都要有crater的話，人類就沒法活了。掉一顆就毀了一地，人家asteroid 里面有iron，沒聽過asteroid 會在經(jīng)過大氣層以后燃燒么，只有一小部分還燒剩一點(diǎn),砸到地球上變成crater.
C.物理化學(xué)沒學(xué)好是吧，trees after the explosion show the force came out like asteroid explosion.而且crater pattern也可以證明不是gas explosion.該pattern 是concerntrated gas不可能形成pot。
（獨(dú)立寫作）
Grades encourage students to learn
1開頭表明自己觀點(diǎn)
Learning is by no means an easy thing, so people often think up various ways to enhance students’ studying efficiency and stimulate students’ studying interest. Many factors are employed to urge students to learn. However, there is no yet absolute agreement on the question whether grades can render students’ encouragement to learn.
As I see it,the answer is by all means!
2理由一 In the first place, grades offer students motives to learn.
3理由二 What is more, grades create a competitive environment of learning.
4理由三 Finally, grades are a good way to measure students’ performance.
5結(jié)尾