Choose the word(s) or phrase(s) which best fill(s) the gap(s). We saw you earlier but we could not stop you because we did not know __________.

Choose the word(s) or phrase(s) which best fill(s) the gap(s).

We saw you earlier but we could not stop you because we did not know __________.

Answer Details

The expression is a reported speech and should maintain the past tense.
Reported speech: a speaker's words reported in subordinate clauses governed by a reporting verb, with the required changes of person and tense (e.g. he said that he would go, based on I will go ).