【正确答案】 C

【答案解析】这是一道细节题，需要问到原文寻找相关信息。A项的依据在第二段开头：“plastics have struggled through a hundred and twenty years of glory，failure，disrepute and suspicion……”说明塑料工业的发展经历了沉沉浮浮 (ups and downs)。B项可以在第二段第二句找到依据：“they make modem life …… more comfortable and convenient…”。D项的依据在本文最后一句：“a great part of the fun of collecting plastics is that beautiful pieces of historical interest can still be found very cheap．”而C项，否认有塑料古董的存在，这与第三段第一句中“the fact that there are plastic antiques”相矛盾，因此是错误的；