共有个核外电子，R的质量数为A，R的中子数是 A． B． C． D．

下列加点字的注音完全正确的一项是(    )。

A．颔(hàn)首恬(tián)静驯(xún)鸽惩创(chuāng)

B．譬(bǐ)如婀(ē)娜蹊跷(qiāo) 陶潜(qiádn)

C．模(mú))样 罪孽(niè)虐(nüè)杀送缴(jiǎo)

D．歆(xīn)羡虔(qián) 诚炽(zhì)热记载(zài)

传说中最后一位通过禅让制产生的部落首领是：

A．尧

B．舜

C．禹

D．黄帝

在△ABC中，角A，B，C的对边分别为a，b，c，若（a+b+c）（sinA+sinB-sinC）=3asinB，则C=______°．

如图是动植物进化历程示意图．据图回答：

（1）根据动植物的形态特征，在动植物图序号的右侧填写动植物类群的名称．

（2）植物进化历程：原始藻类→______→______→______．

（3）最早出现的脊椎动物是______．原始的鸟类和哺乳类是由______进化而来的．

（4）现在的爬行动物还能不能进化成鸟类和哺乳类？

Government officials reported three new cases of mad cow, bringing the total so far this year to 99. Last year, France recorded just 31 cases of the mad cow disease. The rising numbers are in part (1) a new testing program that focuses on cows that are most (2) . That program has (3) 39 cases. But still 60 new cases were identified in the usual way, (4) were found in 1999. Many scientists (5) that this year, five years after safety precautions were (6) , the number of cases would be (7) .

The rise in cases has (8) some scientists to question whether the disease can be transmitted in ways not yet understood. Scientists are still (9) the disease, first recognized in cows in 1986.

It appears that it is not caused by a bacteria, virus or fungus, but (10) infectious particles called prion, perhaps (11) a virus or other agent. The disease kills cells in the brain, (12) it spongy and full of holes.

France has taken more steps to (13) safety than most European countries, (14) refusing to take English beef (15) the European Union. But some scientists believe that France has not been (16) in imposing the ban on feed that (17) animal pans.

Some French officials hope that the sudden interest in mad cow disease will mean that French consumers will become educated about it, thereby recognizing that French beef is actually (18) controlled. Every cow is given a passport at birth, and extensive information about its parentage and (19) it was raised must be (20) to any slaughterhouse. When a diseased animal is found, the entire herd is destroyed.

15（）

A. abiding by

B. in defiance of

C. according to

D. in accordance with