There are many advantages to live on the top of a high-rise, one of which is that you can get a good ______.

Noone has _____ been able to trace the author of the poem.

William found it increasingly difficult to read，for his eyesight was beginning to  ．

Though bought ten years ago,the car is still in good ______.

Everyone who reached the top of Mount Tai was       with a magnificent view.