22、    此题要求改正所给短文中的错误。对标有题号的每一行作出判断：如无错误，在该行右边横线上画一个勾(√)；如有错误(每行只有一个错误)，则按下列情况改正：

    此行多一个词：把多余的词用斜线(＼)划掉，在该行右边横线上写出该词，并也用斜线划掉。

    此行缺一个词：在缺词处加一个漏字符号(∧)，在该行右边横线上写出该加的词。

    此行错一个词：在错的词下划一横线，在该行右边横线上写出改正后的词。

    注意：原行没有错的不要改。

Last summer I was considering how I can make a                    1．__________

contribution to the 2008 Olympics．Finally, I realize my wish               2．__________

during my 19-day tour of America．Stayed with my host family，         3．__________

an old couple in Tucson，US，I came up an idea．Wouldn’t            4．__________

that be a good opportunity to spread the message of the                    5．__________

Olympics to these two Americans? To my surprised，they               6．__________

were real interested in my idea. So I decided to give them a                  7．__________

speech．Apart from a brief introduction to the Beijing Olympic              8．__________

Games，and I offered them other information about Chinese              9．__________

culture．I also invited them to pay visit to Beijing in 2008．                   10．_________

21、    Dams are classified by the type of material used in their construction and by their shape．Dams call be constructed from concrete，stone，loose rock，earth，wood，metal，or a combination of these materials．Engineers build dams of different types，depending on the conditions of the riverbed and the surrounding landshape，and the construction materials．

    Gravity dams use only the force of gravity to resist water pressure — that is，they hold back the water by the force of their weight pushing downward．They are much thicker at the base than the top —a shape that reflects the distribution(分布)of the forces of the water against the dam．As water becomes deeper，it puts more pressure on the dam．Gravity dams are relatively thin near the surface of the reservoir，where the water pressure is light．

    An embankment dam is a gravity dam formed out of loose rock，earth，or a combination of these materials．

    Arch dams are concrete or stone structures that curve upstream into a reservoir，requiting a relatively narrow fiver canyon(峡谷)with solid rock walls able to support a large amount of force．These dams do not need to be as massive as gravity dams because the canyon walls carry part of the pressure from the reservoir．Because．they require less material than gravity dams，arch dams can be less expensive to build．

    A buttress dam consists of a wall，or face，supported by several buttresses every 6 to 30 meters on the downstream side．Buttress dams are sometimes called hollow dams because the buttresses do not form a solid wall stretching across a fiver valley．It falls into two basic kinds：flat slab and multiple arches．Flat slab buttress dams have a flat upstream face．Multiple arch buttress dams have an upstream face formed by a series of arches．

    Like arch dams，buttress dams require less concrete than gravity dams，but they are not necessarily less expensive to build than gravity dams．Costs with the work of forming the buttresses or multiple arches may offset(抵消)the savings in construction materials．Buttress dams may be desirable，however，in locations with foundations that would not easily support the massive size and weight of gravity dams．

1．Which of the following pictures best stands for gravity dams?

2．According to the passage，it generally costs less to build _______．

      A．arch dams than gravity dams             B．buttress dams than gravity dams

      C．gravity dams than arch dams             D．gravity dams than buttress dams

3．Which of the following would be preferred to build in places with foundations not strong enough?

      A．Gravity dams．                              B．Arch dams．

      C．Buttress dams．                              D．Embankment dams．

4．The best title for this passage would be _________．

A．Functions of Dams                           B．Constructions of Dams

C．Costs of Dams                              D．Types of Dams

19、It took the early settlers more than 150 years to build up _______ is now a modern city．

A．where                     B．which              C．what                  D．that

18、一I try to memorize new words every day, but can only remember few of them．

一That’s not surprising．Newly-learnt words are easily forgotten unless frequently _______ in communication．

A．used                       B．using                C．to use                 D．be used

17、During your stay in Britain，you’ll face culture shock      language problems．

A．as far as       B．as long as            C．as good as               D．as well as

16、一Jim managed to get into his house without the key．         ?

一I don’t know．He might have asked someone for help．

A．What for       B．Guess how           C．So what             D．Who knows

15、ack felt grateful to his teachers _______ he couldn’t find words to express it．

A．as if      B．even though         C．so that           D．now that

14、一How can we reduce C0₂ in our home?

一It’s easy．_______ off your TV or computers when you’re not using them，and you’ll greatly reduce it．

A．Turn           B．To turn        C．Turning       D．Turned