在正常刹车失效时备用刹车如何响应 ？

The truth is      （）   he doesn＇t work hard enough.

The reason for his success is        （）          he worked hard.

The problem is not （）        we leave, but  （）         we can get there.

It looks    （）           it＇s going to rain.

This is   （）            .

The news  （）    Lincoln was murdered filled the American people＇s hearts with deep sorrow.

We were all very worried over the fact  （）           you were ill.

Do you doubt        （）            I believe you ?

  （）      cleans the blackboard is to be praised.

Please put the magazines   （）           .