题目内容
It was ______ the president's speech that the secretary spent the whole morning at home.
A. to prepareB. preparing C. prepared D. be prepared
B
【解析】
试题分析：本题中含有一个强调句型，强调的是句子的宾语preparing the president's speech；在英语中，通常动名词可以在句中做宾语。本句中是一个固定搭配spend some time in doing stt花费时间做某事；句义：秘书花了整个晚上在家里准备的正是总统的演讲。故B正确。
考点：考察动名词用法
阅读下列短文并根据所读内容在文章后表格中的空格里填入最恰当的单词，每空格1词（共10个小题；每小题1分，满分10分）
Zebras have their own bug repellent(驱虫剂)?
Eww bugs! They are so annoying! We humans are lucky that we can apply repellents to avoid nasty bites. But what’s an animal to do? They have no choice but to spend their days shooing them off with their tails, unless, of course, they are zebras, who apparently have their own automatic repellent--- their striped skin!
Scientists had originally thought that the reason why the animal had developed the black and white lines was to help protect itself from predators in the African savannah, because the stripes make it difficult to single out one zebra that is traveling with a herd.While that may be true, the theory has never been tested or proven. Now the experts have another---that the stripes have evolved to repel the annoying horse flies that not only feed off their blood, but also, transmit dangerous germs into the bodies of these innocent animals.
The study was performed by a team of Swedish scientists. One of the clues that got them thinking along these lines was the fact that darker horses got bitten more often than light-colored or white ones.
The fact that zebras are born black and only develop strips as they grow older made the scientists theorize that the stripes may be something the animals have developed to make themselves less attractive to flies.
To test if this may be the case, they painted some boards at a horse-infested horse farm in Budapest with patterns of black and white stripes of varying widths and applied a layer of glue on them. What they noticed was that the places where the black and white stripes were at their narrowest (similar to what zebras have) attracted the fewest flies. They achieved similar results when they painted horses with black and white zebra-like stripes.
While the research are not sure why this may be the case, they believe it may be something to do with the way insects operate---horseflies are attracted to horizontally polarized light（偏振光）; since white does not reflect it, white horses are luckier than black ones. But zebras seem to be the luckiest of all. When the researchers measured the polarized light reflected from real zebra skins, they found that it matched light patterns that were the least attractive to horseflies.
While this theory does make logical sense, nobody is 100 percent sure that it is really true, given that it has never been tested on a real zebra. If it is true, it does raise the question of why a horse, a close relative of the zebra has failed to develop stripes. The researchers believe that this could be because there are more horseflies in Africa, where zebras reside, then anywhere else in the world.
Title | Zebras have their own bug repellent? | |
Reasons for zebras developing their strips | Original belief | With the black and white lines, one zebra is difficult to single out while traveling with a herd, thus ___1.___ it from its enemies. |
New theory | Zebras, residing in Africa where there are most horseflies in the world ,have developed strips to avoid being___2.____ . | |
A study | Researchers | A team of scientists from ___3.____ |
____4.____ | To test if strips are developed to make zebras less attractive to flies. | |
Clues | *White or light-colored horses are less __5.___ to get bitten than dark ones. *Zebras develop strips as they grow older though born black . | |
Method | *Some boards at a horse farm are painted with patterns of black and white stripes variously ___6.___ , a layer of glue applied on them *Measured the polarized light reflected from real zebra skins | |
_____7.___ | *The places where the black and white stripes were similar to the ___8.___zebras have attracted the fewest flies *Strips of zebras matched light patterns that were the least attractive to horseflies | |
Principle of zebras’ black and white strips repelling the flies | Horizontally polarized light, which white does not reflect, ____9.___ to horseflies.
| |
Conclusion | ____10.___tested on real zebras, the theory isn’t definitely true. | |