应该选C
但我不得不说一句惭愧 其实一开始我也选的是B 是因为我没看清楚题目
B. Whether the expense of installing the cleaning equipment in a new plant is less than the expense of installing the cleaning equipment in an older plant. 我当时想的是对比安装新的chemical cleaner (也是就是the new one) 的expense和旧的filter的花费的比较 但是我仔细看了看发现其实B选项比较的不是以上两个 我猜当时狗主人应该也犯了同样的错误吧
-- by 会员 melvinperson (2010/11/28 12:27:40)