Please capitalize where necessary: the following extract shows a group of recognizable 20th century characters, to which any attentive student of our times could fit names, yet it was written in 1813:
A: The following extract shows a group of recognizable 20th Century characters, to which any attentive student of our times could fit names, yet it was written in 1813:

Please capitalize where necessary: the use of rovings instead of long-fibre granulate yields a significant cost benefit.
A: The use of rovings instead of long-fibre granulate yields a significant cost benefit.

Please capitalize where necessary: residents in the building are friendly.
A: Residents in the building are friendly.

Please capitalize where necessary: powermatic is at the heart of pottinger silage trailers: powerful, robust and capable.
A:
Powermatic is at the heart of Pottinger silage trailers: Powerful, robust and capable.