人能感受的声音频率有一定的范围,大多数人能够听到的声音的频率范围大约是20-20

题型:选择题

问题:

人能感受的声音频率有一定的范围,大多数人能够听到的声音的频率范围大约是20-20000次每秒.人们把低于20次每秒的声音叫次声波,把高于2000次每秒的声音叫超声波.大象进行交流的“声音”是一种次声波,人类听不到大象的“声音”,是因为(  )

A.大象发出的声音太小

B.次声波无法传到人耳

C.次声波的频率大于20000次每秒

D.次声波的频率小于20次每秒

考点:超声波和次声波的定义
题型:选择题

The first prize winner______, John was so disappointed that he felt unwilling to know the rest results. [ ]

A. announcing

B. announced

C. was announced

D. had been announced

题型:选择题

阅读理解。

                                                                                                                                               CWU

                                                                                                                      The communication union 

Head of Research

Salary: £55.271

     We are looking for a Head of Research to manage the CWU Research Department and Information Centre.

You would be required to exercise control of all research work of the department and manage a team of three

researchers and four support staff.

     The person appointed would be expected to carry out research work of a strategic nature across the range

of businesses in which the CWU has or seeks membership and to contribute to the strategic thinking and

direction of the union as a whole.

     You will need: proven line management skills, especially in managing and motivating a team; good research

skills, holding a good degree in a related subject or other similar experience; a high level of mathematical and

calculating skills; the ability to produce high quality work under pressure; a commitment to and knowledge of

the trade union movement and social democratic politics; and knowledge and/ or experience of the postal and/

or telecommunications industry.

     To apply, please request an application pack by emailing hr@cwu.org or by telephoning HR (Human

Resources ) on 020 8971 7482. When applying please state your source.

Closing Date for Applications: 4th August 2010

Anticipated interview date: 17th August 2010

No agencies please

1. In which column of a newspaper could we find this advertisement?

A. Arts.

B. Sales.

C. Jobs.

D. News.

2. One of the duties of the person to be appointed is _____.

A. taking charge of research work.

B. seeking membership for the trade union.

C. managing a team of three or four members.

D. running a telecommunications company.

3. If you want to apply for this position, you can do all EXCEPT _____.

A. ask an agency for an application form

B. dial 020 8971 7482 for more information

C. email hr@cwu.org for an application pack

D. send in your application before 4th August 2010

4. Which of the following applicants is most likely to be employed?

A. A school teacher with a master's degree.

B. A university graduate majoring in computer science.

C. A director from a research centre with a master's degree.

D. A clerk from a telecommunications company.

题型:选择题

含硫化氢罐在进油、出油调合时,禁止进行上罐人工检尺作业,如确需上罐检尺,必须等罐内液面静置()分钟后方可进行。

题型:选择题

纸张的两面性对印刷的影响

题型:选择题

其它条件不变,提高精馏塔塔底温度,精馏塔的操作压力将()。

A、提高

B、降低

C、不变

D、不确定

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