1. I suggest you should give up the job

2. He has been learning Korean since he was 10

3. More and more air pollution is being produced by that factory

4. In spite of earning a small salary, he is happy

$\textrm{If I were you, I would give up the job.}$

$\textrm{→I suggest you should give up the job.}$

$\textrm{He started learning Korean when he was ten. He was still learning it.}$

$\textrm{→He has learnt/ learned Korean when he was ten. He was still learning it.}$

$\textrm{That factory is producing more and more air pollution.}$

$\textrm{→More and more air pollution are being produced by that factory.}$

$\textrm{Although he earns a small salary, he is happy.}$

$\textrm{→In spite of earning a small salary, he is happy.}$