______ after a long walk, Henry called and said he couldn’t come．
| A．Having worn out | B．Being worn out |
| C．To wear out | D．Worn out |
19. They________a lot of suggestions for improving the workers’ living conditions.
| A．put out | B．put forward | C．put on | D．put in |
18. After having gone____-far, I didn’t want to turn back.
| A．enough | B．thus | C．that | D．Much |
17. One of the mottos for the park makes_____clear that science and business can and must work together to build the future.
| A．them | B．it | C．us | D．This |
16. This experiment turned out to be____failure, but, as we know, success often comes after___failure.
| A．a; \ | B．a; a | C．\; \ | D．\; a |
15. It is often said that the joy of travelling is________in arriving at your destination___in
the journey itself.
| A．\; but | B．\; or | C．not; or | D．not; but |