1、Why Earthquakes and Volcanoes Occur?The Earth is made up of several different layers.In the very centre is the inner core,1 _ is made up of solid metal.It has a temperature of around 5,000.Around this is 2 _ outer core made up of liquid metal.1.引导非限定性定语从句,进一步解释说明inner core。2.core是个可数名词,在此具体指一个。which
2、anThis is surrounded by the mantle which is made up of rock which is so hot 3 _ it is melted.The outermost and 4 _(cool)layer of the earth is the crust.The earths crust is very thin.3.so.that结构,that引导结果状语从句。4.从outermost和and可知，此处用最高级。thatcoolest5 _is made up of about 20 pieces of rock,6 _(call)tecton
3、ic plates,that fit together like a ball-shaped jigsaw.These tectonic plates can contain 7 _land and ocean.They float very 8_(slow)about the earth,bumping into each other and overlapping or drifting apart.5.it在此作人称代词，指代crust。6.过去分词短语作状语,表示“叫作”常用called。7.不定代词，表示两个用both。8.修饰动词用副词。calledItbothslowlyAt t
4、he places where plates meet there is a lot of geological activity and this is where most earthquakes and volcanoes occur.In places where the earths crust is cracked,melted rock(called magma)can leak into the earths crust.Magma mixed with hot gases builds up under the surface and 9 _the pressure beco
5、mes very great,the magma forces a hole in the earths crust.9.引导时间状语从句。whenThen melted rockgas,dust and ash escape.Sometimes volcanoes erupt violently,10 _(push)magma high into the air,but others are gentler,and magma leaks slowly onto the surface,gradually building up into mountains of volcanic rock.10.表伴随动作。pushingcore n.核心mantle n.地幔outermost adj.最外面的crust n.外壳tectonic plate n.地壳构造板块jigsaw n.拼图玩具magma n.岩浆overlap vt.&vi.重叠助读词汇
