together
They worked together in the waterworks
It will soon be three years since we lived together
To mix sand and cement together
with/to/at... each other/one another
The two girls talked (with each other) for half an hour
Successful candidates smiled happily at one another
To introduce two people to each other
between; among
There is a close relationship/correlation/interrelation between industry and trade
Among friends, don't hesitate to tell us the whole truth
Settle it among yourselves!