It was not until 1911, _______ the first vitamin was identified, _______ people realized the importance of it．

    A． when; which     B． when; that      C． that; which     D． that; that

It was ________I went there ________I began to know something about the matter.

A．until；when                           B．until；that

C．not until；that                         D．not when；that

 It was not until she had arrived home _______ her appointment with the doctor.

A. when she remembered                         B. and she remembered

C. did she remember                                  D. that she remembered

Not until they left school ____how much their teachers loved them and helped them.

It was _______ back home after the experiment.

A．not until midnight did he go

B．until midnight that he didn’t go

C．not until midnight that he went

D．until midnight when he didn’t go