问题 选择题

拿来几枚鸡蛋,去除蛋壳和卵黄膜我们会发现,有的卵黄上的胚盘色浅而小,有的卵黄上的胚盘色浓略大,这是因为(  )

A.产蛋母鸡的营养状况不同

B.蛋的大小不同

C.与将来发育成公鸡或母鸡有关

D.是受精卵或未受精卵

答案

已受精的鸡卵,胚盘色浓而略大,这是因为胚胎的发育已经开始了.所以有的卵黄上的胚盘色浅而小,有的卵黄上的胚盘色浓略大,这是因为是受精卵或未受精卵.

故选D

阅读理解

阅读下面短文并回答问题,然后将答案写在横线上(请注意问题后的词数要求)。

     It's safe, it's simple, and it works: Drinking right amounts of water can really help you lose weight, new

research shows.

     In what researchers claim is the firstever trial of the effect of water consumption on weight loss,

scientists from Virginia Tech found that dieters who started each meal with two glasses of water lost nearly five pounds more, on average, than dieters who did not,over the course of 12 weeks. There's no shortage of clear evidence about how water might work to control your appetite (食欲). It ____________ so you don't eat so much; it keeps down your thirst so that you don't turn to calorierich sodas or juices. But until

now, the researchers say, there has been no true evidence that water's appetitecontrolling benefits ever

translate into actual weight loss. Now there is. In the 12week study period, dieters instructed to drink

water with every meal lost an average of 15.5 pounds; dieters given no instructions lost, on average, just

11 pounds.

     Perhaps the most surprising thing about the finding is how little we still know about healthy water

consumption in general. In fact, although doctors and public health authorities regularly remind us to drink more water, very few studies give any insight into what our ideal quantity may be.

     The new results today suggest that many people could indeed stand to drink a little more water than

they do. But if you're looking to lose weight, be aware that it is actually possible to drink too much water,

and you probably won't help matters any by drinking too much water at a time. In extreme cases, it can

even be deadly. A couple of glasses with each meal, however, should be no problem at all for a healthy

person.

1. What is the main idea of the text?(no more than 8 words)

________________________________________________________________________

2. What might your appetite be controlled by? (no more than 3 words)

________________________________________________________________________

3. Fill in the blank in Paragraph 2 with proper words. (no more than 3 words)  

________________________________________________________________________

4. Why should we avoid drinking too much water at a time?(no more than 6 words)

________________________________________________________________________

5. What does the word "it" (Line 1, Paragraph 1) probably refer to?(no more than 6 words)

________________________________________________________________________

单项选择题