Police have asked witnesses of the accident to ___________, as the victim is critically wounded, unable to give an account of the accident.

Everyone needs friendshipNo one can sail the ocean of life single­handedWe need help ________， and also give help to others

I wrote a letter to John for his help during my high school years. without which Ithe college entrance exam.

What are you doing this weekend–We’re going to the Great Wall if it ________.

How do you think that he was an hour late on such a short journey?