天然放射性核素发射出的绝大多数α粒子的能量在()范围。
A.0~4MeV
B.4~9MeV
C.9~10MeV
D.10~100MeV
E.1000MeV以上
参考答案:B
When reading, you should ______ your attention on the main idea and the structure of the passage, not
on specific words or sentences. [ ]
A. pay
B. focus
C. put
D. expand
叉车装载时,货载重心在载荷中心距之外才稳定行驶。