John got his phone for his birthday, his parents don’t let him use it in school.
A. however
B. which
C. but
D. when
网友回答
A. however
B. which
(答案→)C. but
D. when
解析：本题考查连词。However然而，可是；which哪一个；but但是； when既然，当……时候。句意：约翰生日得到一部手机，但是他父母不让他在学校里使用。用于句子中间时，but之后一般不得使用逗号，而however则必须用逗号与句子其它部分分开。故选C。