【单选题】根据下面材料,回答题。 It is predicted that there will be 5 scientific breakthroughs in the 21st century. We'll know where we came from. Why does the universe exist? To put it another way, why is there something...
A.
there was not antibiotics at that time
B.
tuberculosis was a terrible disease that couldn't be cured during 19th century
C.
the health of the heroine was very poor
D.
this was a common situation in the 19th century operas