各负50%责任的碰撞是（）.A.意外、不可抗力原因造成的碰撞 B.原因不明的碰撞 C

Paul Nicklen waited patiently on a sheet of ice in the Arctic.  He was there to take pictures for National Geographic. Finally, he saw something big and white. It was a polar bear, swimming towards him in the icy water.

Paul lay down-on the ice to get a better photo, but the polar bear jumped out of the water and tried to attack him! Luckily for Paul, the ice cracked or broke and the bear fell back into the water The polar bear wasn’t so lucky. It couldn’t get a meal and had to swim farther away to find food.

To understand the polar bear’s problem, you need to know two things about the Arctic. First, the Arctic is mostly ocean. Second , ice cover a lot of the Arctic Ocean. In winter, the ice form a thick, white sheet, but in summer, the ice becomes thinner and break into pieces. Sea ice is the key to survival for Arctic animals. However, because of global warming, Arctic temperatures are rising and polar ice is melting.

Polar bears need ice to hunt seals, their favourite meal. They stand on the ice wait for the seal to come up for air. As Arctic ice melts, polar bears have to swim farther to find ice floes, or large pieces of floating ice. Sometimes, bears have to swim more than 200 km to find an ice floe. Some bears cannot swim that far and sadly they drown.

On his last trip, Paul Nicklen saw three dead bodies of polar bears. Before global warming threatened Arctic ice, a dead bear was a rare sight, Paul is sad to see the dead bodies, wildlife experts thinks global warming will have a terrible effect on polar bears. In the future, polar ice will continue to shrink and endanger the bear. Some scientists believe 65 percent of the world’s polar bears will disappear by 2050. in other word, polar bears are in great danger.

小题1: The main idea of the passage is that_________.

A. polar bears are amazing swimmers          

B. Arctic temperatures are rising

C. global warming is endangering polar bears

小题2:The polar bear that tried to attack Paul was unlucky because

A. Paul swam away                       

B. it was on an ice floe

C. it couldn't eat Paul

小题3:According to the passage, polar bears hunt seals by______ .

A. waiting on the ice                       

B. waiting in the water

C. drowning the seals

小题4: From the passage, Paul Nicklen is maybe a_________.

A. scientist                 

B. photographer   

C. Psychologist

小题5:  We can infer that polar bears____________.

A. won't have any food in 2050        

B. will all die before 2050

C. cannot find food easily

依照《民用爆炸物品管理条例》的规定，爆破器材包括（）。

A．各类炸药

B．雷管

C．烟花爆竹

D．导火索

E．爆破剂

把一张长是6厘米，宽是4厘米的长方形照片放大，放大后的长是15厘米，宽是______厘米．

简述投资项目终结阶段现金流量估算的主要内容。

在综合交通枢纽的衔接中，建立与其吞吐能力相适应的旅客集散和中转系统的客运枢纽不包括______。

A．铁路
B．公路
C．水运
D．机场