service ads, also PSAs, often _________ for free, _________ to educate people about health, safety or any other problem that affects public welfare

okesman did not give out the detailsof the message, saying, “it should not be made public as it is a ______ issue”

I’d like two ________.

When we start gazing into the night sky with a telescope, soon we’ll be astonished by the realization _______ we and our world are part of this giant system.

Some old people don’t like pop songs because they can’t ________so much noise.[ ]