—Was his father strict with him when he was at school?

—Yes.He had never praised him 　　　 he became one of the top students in his grade.?

A.after　　　　　 B.unless

C.until　　　　　 D.when?

----Was his father strict with him when he was at school?

----Yes.He had never praised him　　 he became one of the top students in his grade.

A、after　　　 B、unless　　　 C、until　　　　 D、when

--Was his father strict with him when he was at school?

--Yes. He had never praised him ________ he became one of the top students in his grade.

[　　]

--Was his father strict with him when he was at school?

--Yes. He had never praised him ________ he became one of the top students in his grade.

[　　]