起落架收放的液压源是

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   （）           .

The question is             （）  the film is worth seeing.

You talk as if you   （）      there.

If I had known that, I     （）    so.

The foreign tourists have visited many scenic spots in Shanghai,
  （）    as interpreter