24-18 Most household appliances use electricity only when in use. Many microwave ovens, however, have built-in clocks and so use some electricity even when they are not in use. The clocks each consume about 45 kilowatt-hours per year. Therefore, households whose microwave oven has no built-in clock use 45 kilowatt-hours per year less. On average, than do comparable households whose microwave oven is otherwise similar but has a built-in clock.

Which of the following is an assumption on which the argument depends?

A) Households that do not have a microwave oven use less energy per year, on average, than do households that have a microwave oven.

B) Microwave ovens with a built-in clock do not generally cost more to buy than microwave ovens without a built-in clock.

C) All households that have a microwave oven also have either a gas oven or a conventional electric oven.

D) Households whose microwave oven does not have a built-in clock are no more likely to have a separate electric clock plugged in than households whose microwave oven has one

E）There are more households that have a microwave oven with a built-in clock than there are households that have a microwave oven without a built-in clock.

高亮部分怎么理解？是哪种句式啊，怎么看也不懂！这道题到底什么意思呢？

这道题这么绕，奇怪竟还没有讨论。还是我理解错了？

答案E,我选D

大家说呢？

我觉得D选项是排除他因；将D取非，如果没有built-in clock的家庭更容易去买一个plugged in clock,那么用的电可能会和有built-in clock的家庭多；--> not + weaken;排除他因

应该把最后一句话和前一句话和起来看：households whose microwave oven has no built-in clock use 45 kilowatt-hours per year less. On average, than do comparable households whose microwave oven is otherwise similar but has a built-in clock.

没有built-in clock的家庭 平均起来 比可比较的、其他方面相似的、有built-in clock的家庭每年要少用45 kilowatt-hours的电.