B群链球菌的特异性鉴定试验是 （） A.杆菌肽试验 B.胆汁溶菌试验 C.卵磷脂酶

Penguins are lovely animals. Most people like them. But now as many as 10 of the 17 kinds of penguins are in danger of disappearing. The number of penguins has decreased by ( 减少了) 30% since 1987.

Penguins are black and white birds that live in the southern part of the world. They are common in the Antarctic Continent (南极大陆) ,New Zealand, Australia and South America. Many live near cold waters (水域). But some live near warm waters in Galapagos Islands. Penguins  cannot fly, but  they are fine swimmers. The shape of their body helps them to survive. Penguins eat fish and krill  (磷虾). They have short wings that help them to dive up to 900 feet to catch larger fish. They can swim 10-15 kilometers an hour which lets them protect themselves. They also have lots of body oil that helps in keeping them dry in the water.

The warming of the earth is the reason for the decrease in the number of penguins. The hotter and hotter air has caused ocean waters to become warmer. Higher water temperature has decreased the fish and krill. Some years later these birds are completely unable to reproduce. And many adult penguins die of hunger.

Too much fishing, exploration for oil and oil leaks (泄漏) also make penguins be in danger. Poisonous things in ocean waters are another danger. Penguins also have their enemies, including sharks, seals and sea lions.

小题1:Penguins can do the following except________.

A．diving

B．flying

C．swimming

D．catching fish小题2:Which of the following is NOT the reason for the decrease in the number penguins?

A．The warming of the earth.

B．Too much fishing.

C．Natural disasters.

D．Poisonous things in ocean waters.小题3:What does the underlined word "reproduce" mean?

A．繁殖

B．灭绝

C．迁徙

D．觅食小题4: What’s the passage mainly about?

A．Fish and krill have decreased.

B．Ocean waters are polluted.

C．Sharks and seals are the enemies of pen­guins.

D．The decrease in the number of penguins.

已知HAc的K_a=1.76×10^-5，NH₃的K_b=1.77×10^-5，H₃PO₄的Ka₁=7.6×10^-3，Ka₂=6.3×10^-8，Ka₃=4.4×10^-13，为了配制pH=7.5的缓冲溶液，最好选用下列试剂中的（）。

A．KH₂PO₄与K₂HPO₄

B．HAc与NaAc

C．NH₄Cl与NH₃

D．NaAc与HCl

推动分时系统形成和发展的主要动力来自于( )。

A．系统的有效性

B．用户的需要

C．系统的分时性

D．系统的开发性

在2010年11月召开的坎昆联合国气候大会上，中国代表强调，气候变化是21世纪人类面临的严峻考验，国际社会必须加强合作，共同应对。这表明[ ]

①气候问题从根本上说是一个和平问题

②国家间的共同利益是国家合作的基础

③国际关系健康发展需要协调国家间的利益

④在气候变化问题上各国都应承担相同的义务

A、①③

B、①④

C、②③

D、②④

吸附膜强度