问题 单项选择题

经济发达国家的膳食结构中的显著特点是()。

A.富含膳食纤维

B.优质蛋白质较少

C.以植物性食物为主

D.摄入饱和脂肪酸较多

E.维生素A、维生素B2和钙的摄入均较少

答案

参考答案:D

阅读理解
                   Part of A Bus Schedule

▼A description of the frequency codes are listed at the end of the page for your convenience. If there is no code listed, then the trip operates daily, seven days a week. This schedule is the same one found in the current printed schedule brochure, which you can download above.
▼Click the agency name to find hours of operation, payment methods and driving directions.
▼SHADING: Indicates the Logan Express non-stop bus service.

 
 

 
Read Across
Back to Top
NORTHBOUND
Leave
Leave
Arrive
Leave
Arrive
Arrive
Logan Airport
Boston(South Station)
Portland
Portland
Bangor
Orono-UMaine
~5:55a
5:45a
7:55a
 
7:15a
8:00a
10:00a
9:15a
10:00a
11:55a
12:01p
2:15p
∧2:45p
11:25a
……
1:35p
 
 
 
……
12:01p
1:55p
 
 
 
12:25p
……
2:35p
 
 
 
~1:25p
1:15p
3:35p
 
 
 
1:25p
2:15p
4:10p
4:15p
6:30p
∧6:50p
2:25p
……
4:35p
 
……
3:15p
5:10p
3:25p
4:15p
6:10p
4:25p
……
6:35p
……
5:15p
7:10p
5:25p
……
7:35p
5:25p
6:15p
8:10p
8:15p
10:30p
10:50p
6:25p
……
8:35p
With Concord Trail ways,
no reservations necessary!
Buy tickets on the day of travel.
……
7:15p
9:10p
7:25p
8:15p
10:10p
8:25p
……
10:35p
9:25p
10:15p
12:10a
~11:25p
11:15p
1:25a
 
Important frequency codes for above schedule:
~Trip leaves Boston South Station FIRST before picking up at Logan Airport.
★Trip operates Sundays ONLY
∧Trip operates Fridays&Sundays ONLY
#Trip operates to Logan Airport FIRST before dropping off at Boston South Station
Italics indicate a bus change in Portland.
★★Service to University of Maine at Orono operates only when school is in session, beginning/end is noted under Holiday&College Notices. The service is also listed in our published schedule.
61. Which of the following trips leaves Boston South Station first before picking up at Logan Airport
A.11:15P  B. 6:15P   C. 8:15P   D. 10:00P
62. Which of the following airport departures does NOT stop at South Station in Boston?
A. 9:15 morning bus                     B. 12:25 afternoon bus
C. 5:25 afternoon bus                   D. 9:25 evening bus
63. According to the schedule, when the service is available, how many buses per day go from Logan Airport to the University of Maine at Orono?
A. 1             B. 3              C. 12              D. 17
64. According to the notes under the schedule, when would students NOT be able to get a bus to the University of Maine from Boston?
A.At weekends  B. In session. C. During university holidays. D. In the case of bad weather
65. Which of the following best describes the ticket policy of Concord Trail ways?
A. Tickets must be booked online.
B. Reservations are necessary.
C. Tickets can be bought on the travel day.
D. Discounts are provided for advanced booking.
单项选择题

阅读以下短文,回答下列题:


由我国科学家精确绘制的水稻第四号染色体精确测序图发表在代表国际权威的英国《自然》杂志上。科技部:中国科学院在上海宣布,我国科学家独立完成了“国际水稻基因组计划”第四号染色体精确测序任务,对这一国际计划的贡献率达10%,这是我国迄今为止完成的最大基因单条染色体的精确测序。
刊于《自然》杂志的论文《水稻基因组第四号染色体序列及分析》宣布,中国科学家采用克隆步移法完成了对水稻粳稻基因组第四号染色体全长序列的精确测定。拼接后总长为3500万碱基对,精确度为99.99%,覆盖了染色体全长序列98%的区域,达到国际公认的基因组测序图的标准。
科学家们在完成序列精确测定的同时,还做了大量的研究工作:对水稻第四号染色体所含基因进行预测分析,鉴定出4658个基因,为进一步鉴定这些基因的功能奠定了基础;完整地测定了水稻四号染色体的着丝粒序列,这是迄今首次完成的高等生物染色体着丝粒序列,为研究着丝粒的功能、染色体的稳定性和染色体的复制提供了基础,也为开发可转化的“人工水稻或植物染色体”提供了基础。以蓝天、白云、金色水稻为封面的本期《自然》杂志,同时也刊登了日本科学家对水稻第一号染色体的精确测序。
测序专家工作组组长、中科院国家基因研究中心的韩斌博士告诉记者,第四号染色体的测序工作于2001年4月启动,首先完成精细物理图,然后采用克隆步移法大规模测序,绘制基因组完成图。此外,研究人员还对另一个亚种籼稻品种广陆矮第四号染色体的序列也进行了测定,报道了水稻两个主要栽培稻在基因组成、顺序及DNA序列水平上的一些异同,揭示两者之间的一些亲缘和进化关系,这些数据为将来整个基因水平的比较提供了良好的示范。
韩斌博士还表示,目前世界上有一半以上的人口以水稻为主食。水稻基因组第四号染色体的序列分析结果和今后的功能基因组研究,可获得大量的水稻遗传信息和功能基因,为培育优良性状的水稻新品种打下良好的基础。同时此次测序成果,还将有助于了解小麦、玉米等其他重要粮食作物的遗传秘密,从而推动整个农作物基因组的研究。

下列关于第四号染色体的说法,不正确的是( )。

A.第四号染色体的测序工作于2001年4月启动
B.水稻基因组第四号染色体的序列分析结果,可获得大量的农作物遗传信息和功能基因
C.水稻四号染色体着丝粒序列的完整测定,是迄今首次完成的高等生物染色体着丝粒序列
D.我国采用克隆步移法完成了对水稻基因组第四号染色体全长序列的精确测定