The phrase "a string of offensives" is correct and usable in written English.
It can be used to describe a series of aggressive actions or military operations, often in a conflict or war context.
Example: "The general launched a string of offensives to regain control of the territory."
Alternatives: "a series of attacks" or "a sequence of offensives".
President Mahinda Rajapaksa's government has been widely criticized for abandoning the truce and carrying out a string of offensives after a series of rebel attacks.
More significantly, Operation Mistral 2, as well as Operation Sana, as the first in a string of offensives launched shortly before the end of the Bosnian War, were crucial in applying pressure to the Bosnian Serbs.
Clarkson has come under fire this year for a string of offensive remarks.
She spews out a string of offensive views on Jews, the homeless, people with intellectual disabilities and others while her husband, Dave David Calvittoo), tries unsuccessfully to muzzle her.
Efforts by Nigel Farage's party to shake off claims of unpalatable views in its ranks have been made harder by a string of offensive comments by candidates and other high profile figures.
(Silver's decision wasn't unprecedented: Major League Baseball banned the Cincinnati Reds owner Marge Schott from taking part in team operations in 1993, and again between 1996 and 1998, as punishment for a string of offensive remarks she made about Jews, African-Americans, and Asians).
Paris Brown posted a string of offensive comments on Twitter before she was given the £15,000 a year job to improve relations between Kent police and young people.
The racist faxes sent to Clyburn's office follow a string of offensive, threatening, and destructive incidents directed at Democratic supporters of health care reform legislation.
Princeton's swim team suspension is the latest in a string of offensive and misogynistic email chains from sports teams that have led to suspended or cancelled seasons.
But over the past 18 months, as militants seized vast swaths of the tribal belt and repelled a string of Pakistani offensives, the funding has come under the microscope.
In between a string of major offensives by federal forces have failed to fulfill promises to stop the killing.
