The pain is gone after weeks of the operation, but the scar _____.

Although some unexpected difficulties have ________ in the process, we are confident that we can handle them.

These pictures _______ us of the happy days which we spent together on the campus.

If we_________ sunlight_________ a dry leaf with a piece of glass, it may start burning.

 At the 2003 Special Olympics in Ireland, more than 6,500 athletes from over 150 countries       .