蓄热体
参考答案：
蓄热式加热炉中回收烟气余热，预热燃料、助燃空气的陶瓷元件，分为蜂窝体、蓄热球两种。
After the long holiday with no exercise, it took Steve a month to get back _____ shape. Looking
back _____ the past, he felt so regretful.
[ ]
A. in; on
B. on; on
C. on; to
D. to; to
抽样调查法
