_____ of the students who took part in the military training is 450.
| A．A number | B．A lot | C．Lots | D．The number |
29. ______ that I made a mistake, I made an apology ______ him.
| A．Realized; to | B．Realize; for | C．Having realized; to | D．Realizing; for |
28. ______ on the top of the tower, and you can see the whole city.
| A．Standing | B．To stand | C．Stood | D．Stand |
27. I think that his advice is well worth __.
| A．valuing | B．to be valued | C．of being valued | D．values |
26. Only after we left the building ______ how dangerous the situation had been.
| A．was I realized | B．I realized | C．did I realize | D．I was realized |
24. In my opinion, you must try some of her home-made wine. It’s quite an unforgettable ___.
| A．experiment | B．experience | C．effort | D．skill |