We think that the duty of the police is to (sure) ______ that people are protected from crime.

A．I watched for ten minutes.
B．It was 9: 30 when I set my watch.
C．The time is 9:20.
D．I set my watch 30 minutes ahead.

A．Nice to see you.
B．That’s all right.
C．Me, too.
D．The same to you.