扫描二维码，直接登录
题库 / OG2018-SC-735
The English physician Edward Jenner found that if experimental subjects were deliberately infected with cowpox, which caused only a mild illness, they are immune from smallpox.
which caused only a mild illness, they are immune from
causing only a mild illness, they become immune from
which causes only a mild illness, they are immune to
causing only a mild illness, they became immune from
which caused only a mild illness, they would become immune to
题目分析：
略。
选项分析：
A选项：由于they are immune from smallpox是一个虚拟的情况，即，它是存在于“实验者感染cowpox”的情况下的，因此，其应该用虚拟语气，即，they would become immune from smallpox。
B选项：分词短语causing only a mild illness是伴随状语，其主语为它所修饰的句子的主语，即，experimental subjects。但在逻辑上，引起疾病的应该是 cowpox，而不是experimental subjects。
C选项：本选项错误同选项(A)。
D选项：本选项错误同选项(B)。
E选项：Correct. 本选项在语法和逻辑上均是正确的。
今天看到Manhattan SC上相关的知识点:
1, （曼哈顿SC 6th的P74）Any "cooma -ing" structures are adverbial modifiers. 所以这题里的“causing only a mild illness”只能是伴随状语，而不是简化的定从。
2, （曼哈顿SC 6th的P148）The CONDITIONAL TENSE is formed by combining "would" with the base form of the verb. This construction expresses the future from the point view of the past. 我的理解是would+v.是个条件从句，这里与虚拟语气无关。
如果解读有误，请老师指正。谢谢！
beat the gmat网站说。。用虚拟
if引导的从句里用的是过去时were所以这里是虚拟语气，如果是一般的条件从句，则应遵守主将从现的规则，也就是，if用现在是，主句用将来时。按照ron大神的解释是，would/might/could 在gmat里出现只有两种情况，一种是虚拟语气，一种是can的过去时
登录 或 注册 后可以参加讨论