By laying low and avoiding competition, stylonurines stuck around millions of years longer, while eurypterines were far more diverse and plentiful at their peak.

通过保持低调和避免竞争，苯乙烯尿素的存延长了数百万年，而广翅嘌呤其鼎盛期更加多样化和丰。

What throws a spanner in the works is the layer of polyethylene that makes the cup waterproof, and the lid, which is most often made of polystyrene.

工作中投入扳手的是使杯子防水的聚乙烯层， 以及通常由聚苯乙烯制成的盖子。