—Was his father very 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

—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 very 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 very 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 very strict with him when he was at school?

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

[　　]

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

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

[　　]

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

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

[　　]