Go all out or you'll be behind the times; ________ would be the situation you face.

1. A.
   which
2. B.
   such
3. C.
   so
4. D.
   as

Go all out or you'll be behind the times; ________ would be the situation you face.

[　　]

All of us didn't notice Tom come into the classroom because the light happened to ________ at that time.

All children in the United States have to receive an education, but not all children go to school. A number of parents　　36　not to send their children to school. Such children are known　　37　　 “home-schoolers”. Some parents prefer teaching their children at home　　38 they do not believe schools teach the correct religious (宗教的)　　39 ; others believe they can provide a better educational　　40 for their children by doing so.　　41 , results show home-schooled children often do better than 　　42 on national tests in reading and math.
　　David teaches his three children at home. He 　　43　that his children learn very differently from children in school. Learning starts with the children’s　　44　and questions. For example, when there is snowfall on a winter day, it may　　45　a discussion about climate, snow removal 　　46 , Alaska, etc. Or a spring evening when the family is out　47　the stars is a good time to ask questions about the sky. If the Brazilian rain forests are on TV, it　48　　be a perfect time to talk about how rain forests influence the climate, how deserts are　49　　and how the polar ice caps　50 ocean levels.
　Home schooling is often more interesting than　　51　schools, but critics (批评家) say home-schoolers might be uncomfortable　　52　 with other people in adult life. Critics also say that most parents are not　53　to teach their children. However, most parents don’t have the time or the　　54　to teach their children at home, so schools will continue to be　　55　　most children get their formal education.

Go ahead，talk to your dog.
As many a dog owner will prove, our furry friends are listening. Now, for the doubters, there is scientific proof that they understand much of what they hear. A border collie called Rico can fetch at least 200 objects by name， researchers in Germany say. The dog also appears to learn words for new objects as easily as a 3-year-old child would. Its word-learning skill is as good as that of a parrot or chimpanzee.
In one experiment, the researchers took all 200 items that Rico is supposed to know and divided them randomly into 20 sets of 10 objects each. The dog waited with one of his owners in one room, while an experimenter put a set of 10 objects into another room. Then, the owner told the dog to fetch one of the items. The dog had to go to the other room and bring the object back.
In four trials, Rico got 37 out of 40 commands right. Because the dog couldn't see anyone to get visual clues about what to bring back, the scientists concluded that he must understand the meanings of certain words.
In another experiment, the scientists took one toy that Rico had never seen before and put it in a room with seven toys whose names he already knew. The dog's owner then told him to fetch the object, using a word Rico had never heard.
In 7 out of 10 trials, Rico picked the right object, suggesting that he figured out the answer by process of elimination. A month later, he remembered half of the new names, which further impressed the researchers.
Rico is probably smarter than the average dog, the scientists say. For one thing, he's a border collie, a breed known for its mental abilities. In addition, the 9-year-old dog has been trained to retrieve toys by their names since he was 9 months old.
It's hard to know if all dogs understand at least some of the words we say. Even if they do, they can't talk back. Still, it wouldn't hurt to sweet-talk your pup every now and then. You might just get a big, wet kiss in return!
48．The passage is probably taken from a book on _____
A．pets B．environment    C．culture     D．nutrition
49．It is implied that ____
A．Rico is probably cleverer than the average dog
B．Only a few dogs can talk back to its owner
C．if a chimpanzee is trained ,it can also recognize the names of objects
D．All dogs can understand words
50．How long is it since Rico’s owner began to train him?
A．nine months  B．3years    C．over nine years      D．more than eight years
51．Rico can do all the following except _____
A．understanding the meanings of certain words.
B．picking the right object by process of elimination
C．remembering all of the new names he learned    D．retrieving toys by their names