20世纪60年代，化学家找到了聚乙烯和聚丙烯的催化剂，从此人类进入了什么时代？

Villagers here are poor and couldn'；t afford to buy food for themselves.Their belts are pulled tight against their bony frames.

2024-01-13 竞赛及其他题库

Ruth and I had only a nodding（）before going to the party, but once we got talking, it was like we'；d been friends our whole lives.

2024-01-13 竞赛及其他题库

His insistence on putting users first, and focusing on（）and simplicity, has become deep-rooted in his own company, and is spreading to rival firms too.

2024-01-13 竞赛及其他题库

Like most female athletes, she, the famous world swimming champion was lean（清瘦的） and muscular.

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“The eye of the hunter, or scout, whichever he might be, was small, quick, keen, and restless, roving while he spoke, on every side of him,as if in quest of game（猎物）.

2024-01-13 竞赛及其他题库

His moccasins（莫卡辛鞋） were ornamented after the gay fashion of the natives.

2024-01-13 竞赛及其他题库

以下关于皮皮虾的说法，哪个是正确的？

2024-01-13 竞赛及其他题库

人们常说的“皮皮虾”是以下哪种海洋动物？

2024-01-13 竞赛及其他题库

补体并不只是单一的蛋白成分，而是由一系列的功能蛋白组成的系统。

2024-01-13 竞赛及其他题库

补体激活经典途径中的C5转化酶是

2024-01-13 竞赛及其他题库