[填空题]Severe winter storms have worsened the nation’s usual post-holiday blood shortage, prompting an urgent call today for people to donate blood. Type O blood is the most urgently needed, because it is the universal blood type, meaning it can be safely transfused to most people in an emergency. "The severe winter weather has forced the cancellation of blood drives and limited our ability to collect blood," American Red Cross President Elizabeth Dole said. The Red Cross reported having less than one day’s supply of Type O blood on hand in 18 of the organization’s 38 collection regions. The Red Cross provides about half of the nation’s blood supply. America’s Blood Centers, which supplies most of the rest, also has reported shortages.
Reacting to the shortage, a Pittsburgh blood bank asked 40 hospitals in western Pennsylvania, West Virginia and Ohio to postpone elective surgeries through Wednesday. At least 1,000 donors are needed each day for the next several days to stabilize the su

[填空题]Severe winter storms have worsened the nation’s usual post-holiday blood shortage, prompting an urgent call today for people to donate blood. Type O blood is the most urgently needed, because it is the universal blood type, meaning it can be safely transfused to most people in an emergency. "The severe winter weather has forced the cancellation of blood drives and limited our ability to collect blood," American Red Cross President Elizabeth Dole said. The Red Cross reported having less than one day’s supply of Type O blood on hand in 18 of the organization’s 38 collection regions. The Red Cross provides about half of the nation’s blood supply. America’s Blood Centers, which supplies most of the rest, also has reported shortages.
Reacting to the shortage, a Pittsburgh blood bank asked 40 hospitals in western Pennsylvania, West Virginia and Ohio to postpone elective surgeries through Wednesday. At least 1,000 donors are needed each day for the next several days to stabilize the su

[单项选择]Children born in the winter months already have a few strikes against them. Study after study has shown that they test poorly, don’t get as far in school, earn less, are less healthy, and don’t live as long as children born at other times of year. Researchers have spent years documenting the effect and trying to understand it.
But economists Kasey Buckles and Daniel Hungerman may have uncovered an overlooked explanation for why season of birth matters. Their discovery challenges the validity of past research and highlights how seemingly safe assumptions economists make may overlook key causes of curious effects. And they came across it by accident.
In 2007, Mr. Hungerman was doing research on sibling behavior when he noticed that children in the same families tend to be born at the same time of year. Meanwhile, Ms. Buckles was examining the economic factors that lead to multiple births, and coming across what looked like a relationship between mothers’ education levels and wh
A. uncovers an explanation overlooked by other researchers
B. highlights past researches
C. analyzes the curious effects
D. is an accident

[单项选择]
The storms have resulted in the following EXCEPT
A. death and damage
B. disruption of air services
C. destruction of crops
D. relocation of people

[单项选择]The storms have resulted in all the following EXCEPT______.
A. death and damage
B. disruption of air services
C. destruction of crops
D. relocation of people

[单项选择]In winter, animals have a hard time________ anything to eat.
A. to find
B. to finding
C. to find out
D. finding

[单项选择]In winter drivers have trouble stopping their cars from ______ on icy roads.
A. skating
B. skidding
C. sliding
D. slipping

[单项选择]