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.
10
A、that
B、what
C、it
D、who
【正确答案】：A
【题目解析】：这里缺一个关系代词来引导定语从句。ii不能引导从句。先行词the Black Plague是物，所以关系代词不能用who和what。答案为A。
