Though the “No smoking” signs have existed for long in public places, heavy smokers often ________ them and light up cigarettes.

It is reported that a powerful earthquake ______the Italian island of Sicily early this morning. 

The accident has _____________to be a good thing after all．

Telling twins apart as an adult is hard enough, but what happens when a baby meets someone who____exactly her dad?

(2013·陕西宝鸡模拟)After Queen Elizabeth officially opened the 2012 Summer Olympics, London became the first city ________ three Olympic Games in history.