a.Economic growth has slowed a little.
b.The car slowed down as it approached the junction.
c.The game slowed up a little in the second half.
d.The ice on the roads was slowing us down.
e. You must slow down a little.
f. We hope to slow the spread of the disease.
Is there the difference btw “Slow (sb/sth) up”," slow (sb/sth) down", “slow (sb/sth)”? Are they interchangeable in all 6 sentences?