The phrase "activities at that time" is correct and usable in written English.
It can be used to refer to specific actions or events that were occurring during a particular period.
Example: "During the meeting, we discussed the activities at that time that were impacting our project timeline."
Alternatives: "events during that period" or "actions at that moment".
Many brokerage firms began playing down the retail arm of the business in favor of investment banking activities at that time.
The file then immediately connects Mr. Libbi's activities at that time to Abbottabad, stating, "In mid-2003, detainee moved his family to Abbottabad, PK and worked between Abbottabad and Peshawar".
Your name will be listed in the Commencement Program the following May and you can participate in commencement activities at that time.
This assumption seems to gain its support not only from direct evidence of millet grains and indirect evidence such as the types of tools used for agricultural activities at that time.
Conversely, gill Na+, K+-ATPase activity at that time was significantly higher in triploid than diploid fish.
Tunnelling was a very popular activity at that time, and a great deal of ingenuity went into devising hiding places and routes of escape.
It was imperative that any cultural activity at that time should show to the outside world that China still existed as an undefeated nation.
The simplest explanation for this active interval is that favorable climate conditions (El Niño, West African Monsoon, and sea surface temperatures) encouraged North Atlantic hurricane activity at that time.
The F.B.I. interviewed Mr. Tsarnaev and his family in Boston but found no sign of terrorism activity at that time, the agency said.
Asked if he had been assured by Mr. Fields that Mr. Pellicano was doing nothing illegal, Mr. Grey first said yes, then added: "I don't know that we ever had a specific conversation about illegal activity at that time.
Scholars of religion generally hold that Jainism originated in the 7th 5th century bce in the Ganges basin of eastern India, the scene of intense religious speculation and activity at that time.
