原子在化学变化中那个说法是正确的（）
A.能够再分
B.有时能分，有时不能分
C.不能再分
D.可以变成其它原子
参考答案：C
The officials said the downward trend of H1Nl flu activity did not ____ mean the worst was over. Flu activity
might pick up next year. [ ]
A. greatly
B. necessarily
C. fully
D. nearly
大气中二氧化碳浓度在过去160多年里由约（）ppm上升到约（）ppm。
A.380；500
B.280；500
C.380；400
D.280；400
