Cluster headaches occur in cycles: sufferers can experience several headaches a day for weeks or even months on end.

VOA: standard.2009.12.17

Colville calls this is an almost unimaginable situation for children and other civilians to have to live through for even one day, let alone months on end.

VOA: standard.2009.10.25

Experts say accountability is key in determining the future use of certain practices such as confining thousands of protesters into small areas for hours on end and of some officers removing badge numbers from their uniforms in crowd control situations.

VOA: standard.2009.04.21

Among other things, it calls on the secretary-general to appoint a special representative to lead efforts to end sexual violence.

VOA: special.2009.10.24

Lee sent Stonewall Jackson, with twenty-four thousand men, on a quick march around the western end of Pope's lines.

VOA: special.2009.09.24

The Republican governor proposes to end collective bargaining rights for most public employees except on the issue of wages.

VOA: special.2011.02.25

In the end, they are permitted to meet just once a year, on the seventh day of the seventh lunar month.

VOA: special.2010.02.08

Behind her,in the little room over the porch, a tiny clock ticked loudly on its shelf near the end of the bed.

VOA: special.2010.05.15

At the end of the day, musicians on both sides would play to raise the spirits of soldiers.

VOA: special.2010.07.25

They plan to continue working on it until the end of October when it will be taken apart.

VOA: special.2010.08.13

But instead of going to prison, she was permitted to seek treatment to end her dependence on drugs.

VOA: special.2010.02.28

They got back on the train and keep going until they reached the end of the line.

VOA: special.2009.05.31

Delegates from around the world have agreed on a new plan to end the worst kinds of child labor by two thousand sixteen.

VOA: special.2010.05.17

But some environmental groups say it should be made permanent to end the nation's dependence on oil.

VOA: special.2010.06.19