题目内容：
共用题干Influenza（流感）
Influenza has been with us a long time. According to some Greek writers___1___ medical history, the outbreak of 412 B. C. was of influenza. The same has been suggested of the sickness___ 2___swept through the Greek army attacking Syracuse in 395B. C. Influenza is a disease that moves most quick-ly among people living in___ 3___ conditions,hence,it is likely to attack armies.
___4___ the nineteenth century there were five widespread outbreaks of influenza. The last of the five ___5 ___in 1889 and marked the beginning of the story of influenza in our time.___ 6 ___the recent outbreak,it started in Asia.
For more than forty years before that outbreak,influenza had steadily ___7___ and was be-lieved to be dying out. A new group of outbreaks was___ 8 ___by the great outbreak of 1889一 1890 and for the next quarter of a century influenza remained a constant threat.
In April 1918 influenza broke out among American troops stationed in France. It quickly spread through all the___ 9___ but caused relatively few deaths. Four months later,however,a second outbreak started which ___10___ to be a killer. It killed not only the old and already sick but also healthy young adults. It ___11___ through every country in the world,only a few distant islands in the South Atlantic and the Pacific remaining___12___.It brought the life of whole countries to stop,food___13___stopped and work loss was very great.Before the great outbreak ended,it had killed at ___14 ___ 15 million people. Thereafter,there have been several great outbreaks throughout the world. It is thus___15___that influenza is a terrible infection that we have to pay more attention to.
7._________
A: increased
B: decreased
C: interrupted
D: kept
参考答案：
答案解析：