The rat has many enemies and its greatest enemy is man. Nevertheless, it is the survivor. Although man has 1_______ an unending war against them, rats have 2_______ the world. In almost every country, from the 3_______ cold of the Arctic regions to the unbearable 4_______ of the tropics, rats are 5_______ thriving, increasing and multiplying.
Apart from their ability to 6_______ themselves to varying climate conditions, rats possess another 7_______ that gives them an advantage in extending their boundaries. More so than most other animals, 8_______ snakes, mosquitoes and spiders, they induce fear. Why should this be so? Certainly they carry 9_______ and man is slow to forget the Black Plague 10_______ killed off millions of people in the fourteenth century. Also, rats have been known to bite 11_______ babies, but the number of such attacks is very much exaggerated. One reads 12_______ the danger of being attacked by “a cornered rat", but this belongs to fiction. Rats do not 13_______ your throat, as many would have us believe. 14_______,it is difficult to believe that its appearance can be a source of 15_______ the common black or brown rat can almost be regarded as a frightful creature while its cousin, the squirrel, is quite pretty and gentle.
5
A、be found
B、to be founded
C、to be found
D、to found
【正确答案】：C
【题目解析】：根据句意，老鼠是被发现，所以这里用被动态。发现find的过去分词为found，不定式的被动式为to be found。founded为found（建立）的过去分词。答案为C。
