—_________ on historical facts, it's well worth reading.
| A．To base | B．Having based |
| C．Basing | D．Based |
_____you I owe a thousand apologies____
having doubted your ability.
| A．For; to | B．To; for |
| C．For; for | D．To; to |
______at in this way, the present situation about birds flue doesn’t seem so disappointing.
| A．Looking | B．Looked |
| C．Having looked | D．To look |
______, I think, and all the problems could be settled.
| A．If you make more efforts |
| B．Making more efforts |
| C．A bit more effort |
| D．To have made more efforts |
The TV programme has______on the children as______as the old.
| A．a good effect; good |
| B．a positive effect; well |
| C．a good affect; well |
| D．affect; well |
It was________great shock to the world that two aero-planes crashed into______World Trade Center in New York o September 11th, 2001.
| A．a; / | B．a; the | C．the; the | D．/; the |