The clock ______ last week has gone wrong.

It was a serious mistake, ______ caused by carelessness.

Attention！_______ in the form right now，making sure that every detail supplied is accurate.

Once we discover a mistake, we should not ______ it but correct it immediately, to create better conditions for economic development.

is he?–He is PSY. He sang the song Gangnam Style (《江南Style》).