下列关于江苏省的说法，正确的是[ ]
A．全部位于长江以北
B．地形以平原为主
C．苏北地区经济发达
D．濒临渤海、黄海
答案：B
Warmblooded animals live an active life even in freezing winter, which helps them to________
their normal body temperature. [ ]
A. keep up
B. build up
C. bring up
D. pick up
