question: the proletariat does not cease the class struggle after it has captured political power, but continues it until classes are abolished -- of course, under different circumstances, in different form and by different means.
Capitalize this past sentence correctly.
A: The proletariat does not cease the class struggle after it has captured political power, but continues it until classes are abolished -- of course, under different circumstances, in different form and by different means.

question: width: ca. 5 mm.
Capitalize this past sentence correctly.
A: Width: Ca. 5 mm.

question: turnaround time (tat) is considered to be from date of receipt at the servicing fluke lab until the date of return shipment.
Capitalize this past sentence correctly.
A: Turnaround time (TAT) is considered to be from date of receipt at the servicing Fluke lab until the date of return shipment.