2．In the third argument the author fears that we will ________ if we create life at will.

　　A．change the natural environment around us

　　B．disturb the ecosystem in nature

　　C．suffer from overpopulation

　　D．accelerate the extinction of animals

　　解析：选B　细节理解题。根据文章倒数第二段"We can see that an ecosystem (生态系统) ...I think it could lead to our extinction (灭绝)．"可知，B项正确。

　　3．According to the passage, what's the author's attitude towards cloning?

　　A．Positive.　　　　　 B．Critical.

　　C．Indifferent. D．Supportive.

　　解析：选B　推理判断题。根据全文内容可知，作者并不赞成克隆，对此持批评态度。

　　4．Which of the following would be the best title for the passage?

　　A．To Clone or Not

　　B．Why Should We Stop Cloning?

　　C．Scientific Research on Cloning

　　D．The Advantages and Disadvantages of Cloning

　　解析：选B　标题归纳题。通读全文可知，全文主要从三个方面讲述了我们为什么不要克隆。

　　B

　　Welcome to the Civic Art Museum's Exhibit of West African Art, showing pieces from our collections.

　　Background

　　The peoples of West Africa, including the Yoruba, the Dogon, the Igbo, and the Akan, have a long art tradition. Tribes (部落) in the area have developed different styles of art and architecture that are suited to the climate and available materials and based on their traditions.

　　Gallery A: Photographs of Traditional West African Architecture

　　This section shows historical and contemporary photographs of traditional West African architecture. Of particular interest are the photographs of the Dogon village. The design of the Dogon village is based on the human figure. Certain types of buildings are placed in particular areas according to the Dogon's complex philosophical tradition. For example, the men's houses are placed in the "head" of the village, the leader's house is in the "chest"，and the women's houses are in the "hands"．

　　Gallery B: West African Masks

The art of mask making is well developed in West Africa. Masks are important to West