Pupils attend a class at a primary school in Mexico City, capital of Mexico, on May 11, 2009. Most of Mexican pre-school educational institutions as well as primary and secondary schools resume classes May 11 after days of closure due to the influenza epidemic. [Xinhua]

A woman helps her daughter wear the mask before she walks to classroom at a primary school in Mexico City, capital of Mexico, on May 11, 2009. Most of Mexican pre-school educational institutions as well as primary and secondary schools resume classes May 11 after days of closure due to the influenza epidemic.  [Xinhua]