PP2里几道同类型的题目请教。名词是否加复数。-->pumpkin转移

icepear

Intricate choreographer emphasized the beauty and virtuosity of the nineteenth century prima ballerina, while the male dancer functioned only as her partner until the twentieth century.

答案A

The Mississippi riverboat, which evolved from simpler steamship of the early 1800's, because the dominant form of passenger transport on the Mississippi River.

答案B

Stars provide early astronomer with a reference system for measuring the motions of planets, the Moon, and the Sun.

答案A

这几题都是名词错误，是什么原因？是要加S变成复数形式吗？可是没看到有明显的指示词啊，或者是隐含的复数意思，因为都不可能是一个人，是这样吗？

quekou

我个人的理解

intricate choreographer， simpler steamship, early astronomer 都是可数名词但前面没有冠词，因此要加复数

icepear

谢谢。