By 1999, astronomers had discovered 17 nearby stars that are orbited by planets about the size of Jupiter.

had discovered 17 nearby stars that are orbited by planets

had discovered 17 nearby stars with planets orbiting them that were

had discovered that there were 17 nearby stars that were orbited by planets

have discovered 17 nearby stars with planets orbiting them that are

have discovered that 17 nearby stars are orbited by planets

##### 考题讲解

A选项：Correct. 本选项在逻辑和语法上均是正确的。请注意，定语从句 that are orbited by planets about the size of Jupiter中的一般现在时是正确的。这是因为17颗星星被环绕是一个客观事实，这个动作的时间不受discover的发生时间的影响。

B选项：首先，with planets orbiting them是一个独立主格结构，其应改为修饰stars的定语从句。这是因为，独立主格是状语，修饰的是discover这个句子。在逻辑上，不能说“伴随着星星被环绕，科学家们发现了17颗星星”，而应该是“科学家发现了17颗被环绕的星星”。其次，最后的that were about the size of Jupiter是定语从句，最近的名词为them，但在逻辑上，这个定语从句应该修饰的名词是planets。

C选项：17 nearby stars的定语从句部分是过去时，容易被认为是这些星星过去被环绕，现在不一定了，这是不合逻辑的。该错误同选项(B)。

D选项：独立主格错误同(B)。

E选项：discover宾语部分that 17 nearby stars are orbited by planets的核心词有误。该部分是宾语从句，核心词是动词orbit。但在逻辑上，天文学家发现的肯定是星星，而不是星星周边的行为（注意谓语动词用的是完成时，也就是说，整句的意思是“科学家到现在为止发现了xxx”。显然地，可以说，科学家到现在为止发现了17颗星星（可能之前发现了16颗，最近又发现了一颗，所以是到现在为止有17颗了），但不能说，科学家到现在为止发现了一件事，因为，发现一件事，要么就是发现了，要么就是没发现，没有“到现在为止发现”一说）。