From the words lettered A to D, choose the word that best completes each of the following sentences:
My mother remarked that it was high time we……….preparing supper.
The correct answer is: D
Explanation
My mother remarked that it was high time we started preparing supper.
It's (high) time; past subjunctive expresses that something should be done and that it is already a bit late. As for the structure, it is followed by a subject with a past tense