It was_____she came to see us that we knew her mother was ill in bed.
A,not still
B,just still
C,only until
D,not until
求答案和理由，谢谢
此外问一句，是不是有一个句型：“It is not until .....that.....”？
D否定句可用两种句式表示。 (1)Not until …在句首，主句用倒装。 Not until the early years of the 19th century did man know what heat is. 直到19 世纪初，人类才知道热能是什么。 Not until I began to work did I realize how much time I had wasted. 直到我开始工作，我才认识到了我已蹉跎了几多岁月。 (2) It is not until… that…这是一个强调结构。如本题。
