问题补充：
-- Our English teacher tells us that grammar is a good way to learn English.
--And our teacher says also helpful to sing English songs.
A. study, that was
B. is studying, it’s
C. studying, it’s
D. studied, that was
答案：
A. study, that was
B. is studying, it’s
(答案→)C. studying, it’s
D. studied, that was
解析：本题第一空考查的是动词的非谓语形式，作为主语时相当于三单形式，say+that从句，故选答案为C
