三、读一读,选一选
( )1.当你向别人问路的`时候,你可以说:
_______________________________________
A: Sorry B: How are you? C: Excuse me
( )2.当你询问图书馆在哪里时,应该这样问:
____________________________________
A: Where is the bookstore? B: Where is the library? C: Where is the museum?
( )3.科学博物馆在邮局的附近。应该这样说:
____________________________________
A: The post office is behind the science museum
B: The science museum is near the post office
C: The science museum is in front of the post office
( ) 4. ---- Where is the school ?---- ______________ .
A . It’s my school . B . My school is big . C . It’s next the shop .
( ) 5. She wants to buy ___________ shoes .
A . a B . a pair of C . a pairs of
( ) 6.Get off _______ the cinema .
A . at B . on C . in
( ) 7. Walk straight _________ ten minutes to cinema .
A . to B . at C . for
( ) 8. My friend is reading a book _______ my left .
A . on B .at C. in
( )9. Excuse me .Where is the hospital ?It’s east _______the cinema.
A .on B. at C. on
( )10. Turn right at the cinema. It’s ______ the left.
A. in B. at C. on
( )11.Go_______this road. It’s on the left.
A. straight B. walk C. to
( )12. You can go by the No.12 bus. ______at the park .
A. Get off B. Get on C. Get to
( )13. Then walk straight_____ two minutes .________left at the cinema .you can see it.
A. for; On B. at; Go C. for; Turn
( )14.Sarah:Where is the library? Zhang Peng:
A.It’s in front of the school.
B.Where is the school?
***.is there a library near here?
D.Yes,it is.
( )15.Liu:Excuse me,is there a cinema near here? Policeman:
A.Yes,there are. B.No,there aren’t.
CYes,there is. D,No,there is.
( )16.请问,电影院在哪儿?
A. Where is the cinema ,please。
B. Where is the school,please?
C. Where is the post office,please?
D. Where is the library,please?
( )17.医院离这儿很远吗?
A.You’re welcome. B.No,it’s not far.
***.is the hospital far from here? D.It’s in front of the school.
四、连词成句
1..there a is near here hospital ?
_______________________________________
2. the cinema where is please ?
________________________________________
3. it’s to hospital next the .
__________________________________________
4. home , near , is , my , the , office , post .
________________________________________________
5 . the , next , to , the , hospital , is , cinema .
________________________________________________
6 . your , far , home, here , from , is ?
________________________________________________
7.left at the turn park .
_____________________________________
8.library get can to I how the ?
___________________________________
9.the left on post office the is .
______________________________________
五、排序
( ) Where is the cinema ,please.
( ) Excuse me,is there a cinema near here?
( ) Yes,there is.
( ) It`s next to the hospital.
( ) Is it farfrom here?No,it`s not far.
( ) Thank you.
( ) You are welcome.
六、读下面两篇文章,判断正T误F
A
It’s Saturday afternoon . Sam has no class today . He is going to his grandma’s home . Now he’s on his way . He walks to the bus stop .Then he takes the No. 308 bus . He goes straight for ten minutes . Then get off at the library . Grandma’s home is on the left .
( ) 1. It’s Saturday afternoon .
( ) 2. Sam goes to the bus stop on foot .
( ) 3. Sam doesn’t take the bus .
( ) 4. He goes on the bus at the library .
( ) 5 . He walks straight for 20 minutes .
B
Lucy : Excuse me . Is there a library near here ?
Bob : Yes ,there is . Go straight and turn left . It’s on Green Street on the right . It’s next to a supermarket .
Lucy : Thank you very much .
Bob : You are right .
( ) 1. Lucy wants to go to a supermarket .
( ) 2. The library is far from here .
( ) 3. The supermarket is next to a library .
( ) 4. The library isn’t on Green Street .
( ) 5. Bob knows the place (地点) that Lucy wants to go .
七、看图写一写,每空一词。
How can I get to school ?
First, __________ ___________. Turn left at the second traffic lights. Then ___ ___ again. Next,_____ _____ at the library and _______ __________.Then _________ ___________. You will see the school.
1.煤粉颗粒磨圆度特征
在扫描电镜下观察煤粉颗粒形态,发现煤粉颗粒的磨圆度不同。根据煤粉颗粒有无棱角及其被磨圆的程度,把煤粉颗粒划分为棱角状、次棱角状、次圆状和圆状4个级别(图4-20)。①棱角状:煤粉颗粒的原始棱角无磨蚀痕迹或只受到轻微的磨蚀,其原始形状无变化或变化不大。②次棱角状:煤粉颗粒的原始棱角已普遍受到磨蚀,但磨蚀程度不大,颗粒原始形状仍然可以辨认。③次圆状:煤粉颗粒的原始棱角已受到较大的磨蚀,其原始形状已有了较大的变化,颗粒原始形状不易辨认。④圆状:煤粉颗粒的棱角已基本或完全磨损,其原始形状已难以甚至无法辨认,颗粒大都呈球状、椭球状。
图4-17 扫描电镜下煤粉颗粒特征
图4-18 煤粉颗粒局部表面能谱分析结果
图4-19 扫描电镜下煤岩粉样特征
图4-20 煤粉颗粒的磨圆度类型
初步分析认为,煤粉的磨圆度特征与其来源有关:①煤层中的固有煤粉由于搬运过程中的磨蚀,容易成为圆状、次圆状;②棱角状、次棱角状煤粉主要是受力脆性破坏的结果,这些煤粉主要来源于钻井、压裂、排采工程造成的煤层机械破坏与应力改变,属于后期形成的次生煤粉。
2.煤粉颗粒球度特征
在扫描电镜下观察煤粉颗粒形态,发现煤粉颗粒的球度不同。根据煤粉颗粒三轴长度比,将煤粉颗粒划分为柱状、片状和粒状三类(图4-21)。若煤粉沿一轴延伸为柱状;若煤粉沿两轴延伸为片状;若煤粉三轴长度比接近为粒状。初步分析认为,煤粉球度可能主要与其煤体结构有关:①原生结构煤和碎裂煤,后期遭受冲蚀作用,易形成柱状煤粉;②碎粒煤易形成粒状,后期搬运过程中磨圆较好,呈粒状;③片状煤粉主要来自于鳞片煤和片煤的片状剥落;④糜棱煤受到强烈的构造作用,煤体变形强烈,可以形成多种形态的煤粉。
3.煤粉颗粒表面特征
在扫描电镜下观察煤粉颗粒表面形态特征,发现煤粉颗粒表面特征不同。根据煤粉颗粒表面光滑程度,将煤粉颗粒的表面分为光滑型表面和粗糙型表面两种(图4-22)。一般,煤粉颗粒的粗糙表面主要是许多微小颗粒吸附在大颗粒表面或者小颗粒聚集造成的。
煤粉颗粒的表面特征是由其自身成分所确定的。经过能谱测试,一般光滑型表面颗粒的主要成分为C元素,以有机组分为主(图4-23);而粗糙型表面的颗粒的C元素含量很少,甚至不含C元素,而Fe,O,S的含量大量增加,初步判断粗糙型表面的颗粒主要为无机矿物,可能含有大量Fe2O3和FeS2(图4-24)。且粗糙型表面的颗粒多于光滑型表面的颗粒,这与显微镜下观察的煤粉成分以无机矿物为主相一致(Yingchun Wei et al.,2013)。
图4-21 煤粉颗粒的球度类型
图4-22 煤粉颗粒的表面特征类型
图4-23 煤粉颗粒的光滑表面特征与能谱测试
图4-24 煤粉颗粒的粗糙表面特征与能谱测试
4.煤粉形态的影响因素
利用扫描电镜对原生结构煤、碎裂煤、碎粒煤和鳞片煤的煤岩粉颗粒形态进行观察(图4-25),结合煤层气井产出的煤粉形态特征,从煤体结构方面力图查明不同形态煤粉的成因和煤粉的来源。
图4-25 煤岩的煤粉形态
原生结构煤和碎裂煤的煤岩粉形态特征如图4-25(a)、(b),其颗粒呈块状,颗粒表面相对光滑,棱角分明,颗粒直径较大,不规则。而煤层气井排采中产出的柱状煤粉呈柱状或块状,煤粉表面相对光滑,棱角分明,且不均一,如图4-21(b)。通过二者对比分析,表明煤层气井排采中产出的柱状煤粉可能来源于原生结构煤和碎裂煤。
鳞片煤的煤岩粉形态特征如图4-25(c),其颗粒呈片状,颗粒表面相对光滑,棱角分明,大小不一,不规则。而煤层气井排采中产出的片状煤粉在颗粒二轴方向上具有良好的延展性,颗粒边缘具有较明显的破裂痕迹,煤粉表面相对光滑,如图4-21(a)。通过二者对比分析,表明煤层气井排采中产出的片状煤粉可能来源于鳞片煤。鳞片煤在煤层气排采过程中受剪切应力及流体冲蚀导致煤粉从鳞片煤上片状脱落,形成大量的片状煤粉。
碎粒煤的煤岩粉形态特征如图4-25(d),其颗粒呈粒状,颗粒表面相对光滑,棱角不分明,呈次棱角或次圆状,颗粒直径较小,颗粒大小均一性好。而煤层气井排采中产出的粒状煤粉颗粒三轴长度比较接近,次圆状或圆状,煤粉表面特征具有明显的光滑与粗糙差异性,如图4-21(c),这主要与颗粒成分有关。通过二者对比分析,表明煤层气井排采中产出的粒状煤粉可能来源于碎粒煤。碎粒煤在煤层气排采过程中受剪切应力及流体冲蚀导致煤粉从碎粒煤煤岩上粒状脱落,形成大量的粒状煤粉。
综上所述,通过不同煤体结构煤的煤岩粉形态特征与煤层气井排采中产出的煤粉形态特征对比发现,煤粉的形态特征与煤体结构有关,不同显微形态特征的煤粉,在一定程度上反映了煤粉的成因和来源。不同煤体结构煤产出煤粉的倾向性不同(表4-15),原生结构煤和碎裂煤以块状断裂的方式形成以柱状或粒状为主的煤粉,颗粒较大,棱角较分明,煤粉产出的倾向性较小;碎粒煤形成以粒状为主的煤粉,粒度较小,煤粉产出的倾向性较大;鳞片煤以片状剥落的方式形成片状煤粉,煤粉产出的倾向性亦较大。
表4-15 不同煤体结构煤产出煤粉的显微形态特征