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举一反三
【单选题】Most shoppers know the feeling. You stand in front of piles of organic produce and wonder what those premium prices are buying you over and above what you get from standard foods. Not a lot nutrition-...
A.
do not use naturally produced fertilisers
B.
produce carbon dioxide when removing weeds
C.
use high doses of weed-killer
D.
use too many resources to qualify for organic status
【单选题】下列有关热水加热器的说法不正确的是（）。
A.
主要用于对供入洗消帐篷内的水进行加热
B.
每次使用完毕，擦拭热水罐外部及燃油过滤器
C.
每6个月擦拭泵内过滤器和用酸性不含树脂的润滑油擦拭燃烧器马达
D.
每使用300次点火器喷嘴后，检查是否积碳，并擦拭干净