[单项选择]Pigiron, wrought iron, and steel contain iron carbides made up of ______ of carbon.
A. (amounts are different
B. ( different amounts that
C. ( different amounts
D. ( which amounts are different

[单项选择]Although all sedimentary rocks contain iron, (but the deposits) that (are richest) in iron (consist) predominantly of minerals (such as) iron oxides, carbonates, silicates, and sulfides.
A. but the deposits
B. are richest
C. consist
D. such as

[单项选择]An iron and steel works, with several satellite factories, ______ in that city now.
A. is built
B. is being built
C. were built
D. are being built

[单项选择]Steel is _____ from iron which contains a certain amount of carbon.
A. composed
B. consisted
C. made
D. produced

[单项选择]Iron and steel expands when heated and ______ when cooled.
A. shrinks
B. contracts
C. condenses
D. compresses

[单项选择]Steel is an alloy composed （） of iron and carbon.
A. primarily
B. traditionally
C. carefully
D. partially

[单项选择]The wrongly-designed iron-steel bridge was finally
A. shipped away
B. sold at a low price
C. made into many rings
D. used again after repairing

[单项选择]Steel works are encouraged to purchase ______ iron so as to reduce the consumption of natural resources.
A. scrap
B. scrape
C. scratch
D. snap

[单项选择]Iron and steel are flexible. But they are not as flexible ______ rubber.
A. as
B. to
C. for
D. by

[单项选择]Steel is an alloy composed ______of iron and carbon.
A. primarily
B. traditionally
C. carefully
D. partially

[单项选择] ____ is rooted in experiments in iron and steel conducted in the nineteenth century.
A. While the history of twentieth-century architecture
B. The history of twentieth-century architecture
C. That the history of twentieth-century architecture
D. Both twentieth-century architecture and its history

[单项选择]At present, there is a ______ of iron and steel and more must be produced.
A. Limit
B. loss
C. poverty
D. scarcity

[单项选择]English iron smelters and English iron manufacturers were both opposed to _______.
A. high import taxes on American pig iron
B. the growth of iron manufacturing in America
C. the shipping of iron products to America
D. selling English wool to the colonists

[单项选择]Specifications for software should contain several components, e. g., specifications of information flow, user interface, functional requirements, and design constraints. Two other important components are specifications of the( ).
A. methods of testing and ways to obtain quality assurance
B. criteria for testing and ways to obtain quality assurance
C. methods of testing and criteria for function assurance
D. criteria for testing and methods of function assurance

[单项选择]Which VPN router does not contain customer routing knowledge?（）
A. Provider Core (P)
B. Provider Edge (PE)
C. Customer Edge (CE)
D. Customer Boundary (CB)

[单项选择]Which of the following would contain information regarding network device alerts using SNMP?（）
A. Syslog
B. Audit log
C. History log
D. Ping sweep reports

[单项选择]Seminiferous tubules contain all of the following components EXCEPT
A. Sertoli cells
B. Spermatocytes
C. A fibrous connective tissue tunic
D. Skeletal muscle in their tunica propria
E. A germinal epithelium

[单项选择]

Text 3
Most growing plants contain much more water than all other materials combined. C. R. Bames has suggested that it is .as proper to term the plant a water structure as to call a house composed mainly of brick a brick building. Certainly it is that all essential processes of plant growth and development occur in water. The mineral elements from the soil that are usable by the plant must be dissolved in the. soil solution before they can be taken into the root. They are carried to all parts of the growing plants and are built into essential plant materials while in a dissolved state.
The carbon dioxide (CO₂) from the air may enter the leaf as a gas but is dissolved in water in the leaf before it is combined with a part of the water to form simple sugars -- the base material from which the plant body is mainly built. Actively growing plant parts are generally 75 to 90 percent water. Structural parts of plants, such as wood
A. The mineral elements will not be absorbed by the plant unless they are dissolved in its root
B. The woody stems contain more' water than the leaves
C. Air existing around the leaf is found to be saturated
D. Only part of the carbon dioxide in the plant is synthesized