關係子句前後不加逗號時為「限定用法」。
例 I have a sister who lives in America. 我有一個住在美國的妹妹。
→ 我還有其他妹妹，故需加以限定才能清楚溝通。
關係子句前後加逗號時為「非限定用法」，具「補述」的作用。需注意，非限定關係子句的關係代名詞不論「表人」或「非表人」皆不可用 that 來代替。
例 I have a sister, who lives in America. 我有一個妹妹，她住在美國。
= I have a sister, and she lives in America.
→ 我只有一個妹妹。（因僅一個妹妹，無限定必要。）
(A) who is known as
(B) who is known for
(C) that is known as
(D) that is known for
(E) she is known as
答案：(B)
翻譯：蛋糕是我祖母烤的，她以美味的甜點與廚藝「著稱」。
解說：這個題目的考點有二：首先須理解片語 be known for（指一個人因為某個特點或技能而出名）與 be known as（指一個人被稱為某個名字或頭銜）的差別。很顯然，此句是要表達奶奶因為她美味的甜點和烹飪技巧而出名，因此選項 (A)(C)(E) 可先排除。 其次，此關係子句是具補述作用的「非限定用法」，逗點後面的部分還原之後為單句 She is known for her delicious desserts and culinary skills，在此用關係代名詞 who 代替主詞 she，引導關係子句修飾先行詞 my grandmother，故正確答案為 (B)。
Q1:【105 學士後醫-中國】
An understanding of child development is essential because it allows us to fully appreciate the cognitive, emotional, physical, social and educational growth _______ children go through from birth and into early adulthood.
(A) who
(B) that
(C) where
(D) what
(E) how
Q2: I watched two new films, _______ was very interesting.
(A) both of them
(B) both of which
(C) either of them
(D) neither of them
(E) neither of which
答案💡1. (B) 2. (E)
