Question

15. Only those ______ knew well could be admitted to the party. A. he B. that C. who D. whom

15. Only those ______ knew well could be admitted to the party.
A. he B. that C. who D. whom
求解
需要理由，分析句子成分

Answer 1

这个正确答案应该是 A
分析：
考察定语从句，句子缺少的成份，可以是人称代词，也可以是人名。
he/she/we/they/you/I/Tom/Bob这些都可以。
补充完整为：
Only those( whom )he knew well could be admitted to the party. whom省略啦。
翻译：只有他很熟悉的人才允许参加聚会。

不能选C ，因为who knew well这个定语从句缺少宾语，属成份残缺。
也不能选B，因为定语从句中，that并不能代表前面的those，表示人称身份，that并不具备实体意义。

Answer 2

选C
定语从句，who 引导修饰前面的先行词those, 在从句中作主语

Answer 3

选B