In each of the following sentences four words or phrases have been underlined. One underlined part in each sentence is not acceptable in standard English. Pick up that part and mark its number.
In English, “while” is used to indicate that two events are happening at the same time. However, in this sentence, it’s unlikely that the person was in an unconscious state at the exact same time the policeman picked him up.
A more appropriate word could be “before” or “until”. So, the corrected sentence would be:
“He lay for an hour in an unconscious state before a policeman picked him up.”
This means that the person was unconscious for an hour, and then a policeman came to his aid.