學測倒數衝刺：不能不會的文法題(8)

Green tea is dried but not fermented, and this shorter processing gives it a lighter flavor than black tea. It also helps retain the tea’s beneficial chemicals. That is __(20)__ green tea is so good for health.
(A) whether (B) whenever (C) what (D) why
[97 學測]

解答：D

解析：
「That is + 疑問詞」意思為「這就是(為什麼等)」。
why是副詞，後面接的是句構完整的子句。
檢查一下：why green tea (主詞) is (動詞) so good for health [相當完整喔！]

本題其他選項，填入空格後不是句意不合，就是文法不對。
(A) whether 無論是否(+ 完整子句) [句意不合]
(B) whenever 每當(+ 完整子句) [句意不合]
(C) what 複合關係代名詞(+ 不完整子句)