Please capitalize where necessary: messages – where teachers can post messages for the course participants in the group.
A: Messages – where teachers can post messages for the course participants in the group.
Q: hôtel le centenaire brussels expo is located a short distance from the famous atomium, on the grounds of the brussels...

A: Hôtel Le Centenaire Brussels Expo is located a short distance from the famous Atomium, on the grounds of the Brussels...
Q: the public schools/de - democracy-handbook.org
A: The Public Schools/de - democracy-handbook.org
Problem: you should identify your checked baggage with your name and address and contact telephone numbers and/or your flight reservation number. .
Can you repeat this sentence, but capitalize it?
Answer: You should identify your checked baggage with your name and address and contact telephone numbers and/or your flight reservation number. .
Text: beijing - implementation of the apec summit in 2014 in beijing, china became the arena of interests between the two shaft power of the world economy, the united states on one side with china and russia on the other.

Correct capitalization: Beijing - Implementation of the APEC summit in 2014 in Beijing, China became the arena of interests between the two shaft power of the world economy, the United States on one side with China and Russia on the other.
Text: what impression do you have in general the opinion of the population of united kingdom? especially young people who in the end and after who live more years conditioned the decision expressed today at the polls if such measures are applied, largely supported by the people of advanced age.

Correct capitalization:
What impression do you have in general the opinion of the population of United Kingdom? Especially young people who in the end and after who live more years conditioned the decision expressed today at the polls if such measures are applied, largely supported by the people of advanced age.