The sun was shining, ___ the sky was blue.
and
The sun was blue, ___ it was very cold.
but
It may rain tonight, __ it may be clear.
or
It was raining outside, __ I took my umbrella.
so
Tom is tall, ___ Paul is short.
but
Tom told a joke, __ Paul laughed.
so
Tom is singing, ___ Paul is dancing.
and
