11．It may seem crazy when you watch your dog bury his bone，only to dig it up a day or two later．（36）DIt is simply in their nature．For thousands of years，dogs have buried their bones．The practice itself started long before dogs were even pets when their ancestors（祖先） had to bury bones to survive．（37）F
If they were able to find meat and bones，dogs became very protective of them．To keep other dogs and animals from stealing their meat and bones，dog would bury them in the ground．When it was time for the next meal，they would dig their bones and enjoy them again．
Although most dogs have plenty of food to eat today，their instincts（直覺） still tell them to bury their bones．Some dogs hide more than one at once，burying one and digging up another．（38）BSo how do dogs decide where to bury their bones？A dog can't just bury a bone anywhere．（39）AThis involves using his nose to sniff（嗅） out a spot that is free from predators（捕食動物）．Often it is near a tree or a large rock．Once the dog finds the satisfying spot，he uses his front paws（爪） to dig the hole，drops in the bone and cover up the hole to protect his treasure．（40）G
Thankfully，dogs have an excellent sense of smell．A dog can smell a bone though it has been buried for years．Dogs can find their bones buried by themselves as well as by other dogs．to the dog，whatever he finds is a treasure．
A．He must first find the perfect spot．
B．This can leave a background full of holes and bones．
C．Dogs use their nose to find a spot to bury their bones．
D．But there is actually a reason behind why dogs bury their bones．
E．Therefore，it's the dogs'instincts that tell them to bury their bones．
F．When dogs lived in the wild，sometimes there was not enough food．
G．Unfortunately，sometimes dogs do not always remember where a bone is buried．
分析 本文屬于說明文閱讀，作者通過這篇文章主要向我們描述了狗喜歡挖洞和埋骨頭的行為的由來和具體方式．
解答 36．D．推理判斷題．根據(jù)后文It is simply in their nature．For thousands of years，dogs have buried their bones可知事實上狗為什么會埋骨頭是有原因的；故選D．
37．F．推理判斷題．根據(jù)前文The practice itself started long before dogs were even pets when their ancestors（祖先） had to bury bones to survive可知當(dāng)狗生活在野外，有時沒有足夠的食物；故選F．
38．B．推理判斷題．根據(jù)前文Some dogs hide more than one at once，burying one and digging up another可知它們挖洞埋骨頭的行為導(dǎo)致了充滿骨頭和洞穴的土地；故選B．
39．A．推理判斷題．根據(jù)后文This involves using his nose to sniff（嗅） out a spot that is free from predators（捕食動物）．Often it is near a tree or a large rock．Once the dog finds the satisfying spot可知他必須首先找到完美的地點挖洞；故選A．
40．G．推理判斷題．根據(jù)后文Thankfully，dogs have an excellent sense of smell．A dog can smell a bone though it has been buried for years可知不幸的是，狗總是忘記骨頭埋在哪里；故選G．
點評 七選五閱讀是完成性閱讀，和完形填空很類似，不同的是一個選詞，一個選句子．解題時，要注意上下文語境，充分考慮信息詞（選項中和空格前后句子中相同或相近的詞），選出最符合語境的句子．
