Leaving port,passengers can see two sets of sea walls built hundreds of meters from shore.

VOA: special.2009.06.01

Her first plane had two sets of wings,a bi-plane.

VOA: special.2010.05.26

"There are two sets of issues," "One relating to the numbers of warheads and launchers that each side would be allowed under the treaty there are some differences between the two sides.

VOA: standard.2009.12.07

The agreement sets targets to prevent the Earth's average temperature from rising more than two degrees Celsius above pre-industrial levels.

VOA: special.2009.12.26