The phrase "activity has resumed" is correct and usable in written English.
You can use it to indicate that a previously paused or interrupted activity is now back in progress.
Example: "After the brief delay due to weather conditions, all scheduled activities have resumed."
Alternatives: "operations have restarted" or "tasks are back on track."
The 24-hour activity has resumed.
But just as Mangum has reanimated, E6 activity has resumed.
Merger activity has resumed in 2011 with a textbook deal: DuPont's $5.8 billion cash offer for the Danish company Danisco, disclosed on Monday.
But this activity has resumed in recent weeks, and there has even been a handful of short films in which he's responded to fans' questions put to him on Twitter.
In cases where brain activity has indeed ceased for a given patient, the NDE may have occurred either before the cessation or after normal brain activity has resumed; it is not necessary to assume that the NDE and the brain's non-activity were simultaneous ("Living Persons").
The patient was asymptomatic and has resumed his activities.
INSIDE PITCH JOSÉ REYES has resumed baseball activities after suffering from soreness and swelling in his lower back the past two weeks.
"The fires are out, the inmates are no longer doing anything dangerous, and the nearby community has resumed normal activities.
HIS e-mail messages reveal a spirit of great equanimity and eloquence: Mr. Wickman, who now wears a prosthesis and has resumed athletic activities, will attend graduate school in the fall for a joint degree in social work and divinity.
The disabilities found include varying degrees of dysphasia, hemiparesis, or ataxia, as well as intellectual and memory deficits and personality changes, and IV) good recovery: the patient has resumed normal activities even though there may be minor neurological or psychological deficits.
Oil bought today below $60 a barrel can be released back into the market at $120 after economic activity has picked up and inflation has resumed.
