______ it have been the failure to pick up directions from the ground control that caused the air crash?
As we all know, one unfortunate outcome of Internet use is that it damages people’s ability _______ normal lives.
—Are you against the Internet, Zhu Fei? —No. I believe that the Internet has positive effects on our lives and there are two main points _______ must be included when we analyse it.
Money and education change Pip. Before long he becomes vain and ashamed of his background and dislikes it _______ Joe comes to visit him in London.
It was so dark that I couldn’t ______ the words written on the wall.
Because a lot of classics were written so long ago, their language characteristics are quite different from ______ of modern works.