It was not until she had arrived home ________ remembered ________ the key in her office．

A.when she; to leave

B.and she; leaving

C.that she; leaving

D.she; to leave

答案及解析： C

解析：

从句型来看，第一空处填that，构成not until的强调句；

remember doing sth。表示“记得做过某事”。