Text: complete this nice puzzle piece.

Correct capitalization: Complete this nice puzzle piece.

Text: as with international summits the ground work is most important, and prior to the visit we had had close email contact with exchange of ideas and suggestions for future cooperation.

Correct capitalization: As with international summits the ground work is most important, and prior to the visit we had had close email contact with exchange of ideas and suggestions for future cooperation.

Text: krishm , 36 years old, united kingdom

Correct capitalization: Krishm , 36 years old, United Kingdom

Text: as a young boy smullyan loved both music and science and he was extremely talented musically.

Correct capitalization:
As a young boy Smullyan loved both music and science and he was extremely talented musically.