Question

    Gardeners may be able to cut down on the amount of weeds killer they use by dealing with invaders （入侵物） at specific times of the day， such as dawn， a new study suggests．

Researchers at the University of Bristol have discovered that the 24﹣hour rhythms of plants leave them more defenseless to herbicides （除草剂） at different points in their daily 24 hour cycle．

They believe the findings could help farmers by reducing crop loss and improving harvests． And gardeners could benefit from knowing which weeds respond better at certain times of the day． In recent years， pesticides and herbicides have been implicated in the decline of important pollinating insects， such as bees．

Dr． Antony Dodd， senior author of the new study， said， "The research suggests that， in future， we might be able to improve the use of some chemicals that are used in agriculture by taking advantage of the biological clock in plants．

Just like humans， plants have evolved to take advantage of cycles of night and day， with certain biological processes turning on at different times of the day． Scientists have discovered that many drugs work much better in humans if they are given at specific hours． Aspirin， for example， has doubled the impact on thinning the blood if taken at night as opposed to in the morning． The process is known as 'chronotherapy （时间疗法）' and researchers wanted to find out if the same concept could be applied to plants．

Many gardeners already know that plants drink in more water in the morning because their pores （气孔） are open to take advantage of early morning dew and water vapour． At the break of he day， plants are also not busy producing food through photosynthesis （光和作用）． The open pores could also be the reasons that chemicals are more effective at dawn and also at dusk．

The air is also likely to be stiller at dawn and dusk， meaning that pesticides or herbicides are less likely to be blown away to places where they are not wanted． Pesticide labels often warn against spraying on windy days in case they endanger people or animals． Many insects are active early in the morning and around dusk， also making very early morning and early evening effective times for insecticide．

Commenting on the study， Dr． Trevor Dines， Botanical Specialist at the conservation charity Plantlife， said， "This is fascinating research which will be of great interest to many gardeners like me． If anything they used to think the opposite was true ﹣that applying herbicides and pesticides late in the day would be better as they'd remain in wet contact with the plant for longer in the cool of the night and therefore be taken up or absorbed more effectively． This research knocks that assumption on its head．"

1.Which of the following can replace the underlined phrase "implicated in" in the third paragraph？

A.restored to

B.blamed for

C.limited to

D.composed of

2.According to the research， what are the reasons for using herbicides in the morning？

A.The process of photosynthesis is most active in the morning．

B.Insects are more defenseless in the morning than any other time of the day．

C.Bigger pores on the plants make herbicides work more effectively．

D.The stronger morning wind blows pesticides away to more places．

3.What is the main idea of this article？

A.New chemicals have been found to help kill harmful insects．

B.Biological clock of plants could help gardeners use less weed killer．

C.Plants' cycles can be taken advantage of to improve the environment．

D.The research on the effects of pesticides has enabled good harvests．

Answer

1.B

2.C

3.B

【解析】

这是一篇说明文。文章介绍了一项新的研究表明，园丁可以利用植物的生物钟来减少除草剂的使用量。

1.

短语猜测题。根据画线词前的“pesticides and herbicides ”可知，杀虫剂和除草剂在杀死害虫和除去杂草的同时还对蜜蜂等重要授粉昆虫产生影响，会导致它们数量的减少，由此可知画线词词义为“归咎于”，故选B项。

2.

细节理解题。根据第七段中的“Many gardeners already know that plants drink in more water in the morning because their pores(气孔) are open to take advantage of early morning dew and water vapour.”及“The open pores could also be the reasons that chemicals are more effective at dawn and also at dusk.”可知，许多园丁已经知道，植物在早晨喝更多的水，因为它们的毛孔是开放的，可以吸收清晨的露水和水蒸气，开放的毛孔也可能是化学物质在黎明和黄昏时更有效的原因，由此可知，在清晨使用除草剂的原因是植物上更大的毛孔使除草剂更有效地发挥作用，故选C项。

3.

主旨大意题。通读全文，并结合第一段内容“Gardeners may be able to cut down on the amount of weeds killer they use by dealing with invaders(入侵物) at specific times of the day, such as dawn, a new study suggests.(一项新的研究表明，园丁有可能通过在一天中的特定时间例如黎明时处理入侵物，而减少除草剂的使用量)”可知，本文主要介绍了一项新的研究表明，园丁可以利用植物的生物钟来减少除草剂的使用量，故选B项。