从生物圈的物质构造来说，它存在着几大类成分，下列选择中有误的一项是( )。A．已经获

下列方法可使海水转化为饮用水的是(　　)。

A．过滤

B．静置沉淀

C．活性炭吸附

D．蒸馏

有以下结构体说明和变量定义，如图所示，指针p、q、r分别指向一个链表中的三个连续结点。　　struct node　　{ int data;　　　struct node *next;　　} *p, *q, *r;　　

　　现要将q和r所指结点的先后位置交换，同时要保持链表的连续，以下错误的程序段是（ ）。

A．r-＞next=q; q-＞next=r-＞next; p-＞next=r;

B．q-＞next=r-＞next; p-＞next=r; r-＞next=q;

C．p-＞next=r; q-＞next=r-＞next; r-＞next=q;

D．q-＞next=r-＞next; r-＞next=q; p-＞next=r;

循环链表的主要优点是( )。

A．不再需要头指针了

B．从表中任一结点出发都能访问到整个链表

C．在进行插入、删除运算时，能更好的保证链表不断开

D．已知某个结点的位置后，能够容易的找到它的直接前件

河南某进出口公司(一般纳税人)2006年3月份从国外进口一批机器设备共20台，每台货价120000元人民币，包括运抵我国大连港起卸前的包装、运输、保险和其他劳务费用共计50000元；另外销售商单独向该进出口公司收取境内安装费用5万元，技术支持费用7万元，设备包装材料费8万元。假设该类设备进口关税税率为50%，境内运费已经取得合法的货物运输企业的发票。该公司应交纳的关税是( )元。

A．2540000

B．2320000

C．1850000

D．1240000

Passage Four

The face of the 21^st century is already growing in a laboratory. Getting a piece of the new look could soon be as simple as writing a cheque.

Scientists in recent years have made giant leaps in the artificial production of skin, bones and tissue. While their research has been motivated by a desire to help accident and medical victims, their work is about to go commercial.

The burgeoning (萌芽) cosmetic surgery market has snapped up the technological advances. By the turn of the 21^st century, changing your face or improving your body will be limited not by your imagination or desire, but by the size of your bank account.

And there is even work being clone on that, with the costs of cosmetic surgery being cut to make it affordable and accessible for the average woman and her partner.

"It’s no longer a vanity thing, it’s simply making use of the available technology to improve those parts of the body you might not be happy with," Cindy Clovetti, a Toronto-based skin and beauty care expert, said. "People who 10 years ago said they would never use a computer and would never get a boob job (胸部整形手术) are now surfing the web getting the latest information for their next operation. "

Latest figures in the United States indicate the number of patients receiving cosmetic surgery in 12 months will top the magic million within two years (there were 850 000 last year), while the number of men seeking image-improving operations has increased 35 percent in the past four years.

Breast implants are now very much a bread-and-butter job for many cosmetic surgeons and the big advances have been made in the development of bone implants which can produce instant high cheek bones, sculpture better shaped noses and ears and give men the chisel-shaped jaw that is always a sure-fire (必定成功的) chick-magnet (吸引女人的东西).

British futurologist Ian Pearson speculates that by 2020, up to 96 percent of body weight will be replaceable with the brain being the only organ not interchangeable. "By 2020 you could have a new face, or new skim. and by 2030 a fully working replacement body part. By the end of the 21^st century, people will be able to get an entirely new body. "

Now the main business of many cosmetic surgeons is ().

A．breast implant

B．bone structure improvement

C．facial beautification

D．skin replacement