单选题 Some cleaning fluids, synthetic carpets, wall paneling, and other products release toxins, such as formaldehyde and benzene, into the household air supply. This is not a problem in well-ventilated houses, but it is a problem in houses that are so well insulated that they trap toxins as well as heat. Recent tests, however, demonstrate that houseplants remove some household-toxins from the air and thereby eliminate their danger. In one test, 20 large plants eliminated formaldehyde from a small, welt-insulated house. Assume that a person who lives in a small, well-insulated house that contains toxin-releasing products places houseplants, such as those tested, in the house.
Which one of the following can be expected as a result?

A、 There will no longer be any need to ventilate the house.
B、 The concentration of toxins in the household air supply will remain the same.
C、 The house will be warm and have a safe air supply.
D、 If there is formaldehyde in the household air supply, its level will decrease.
E、 (E) If formaldehyde and benzene are being released into the household air supply, the quantities released of each will decrease.

【正确答案】 D

【答案解析】[解析] 本题的结论为室内盆栽植物可以吸收空气中的毒素。因此若一个密闭性良好的房间内有释放毒素的产品时，放入较多的室内盆栽植物后，室内的空气中的毒素肯定会下降，所以(D)为正确答案；(B)为明显错误的选项；(E)具有迷惑性，但(E)错在每种毒素物质的释放量均会下降上，我们知道室内盆栽植物只能吸收毒素，而不能抑制毒素的排放；(A)和(C)都不能从本题的论述中合理地推出。