about time = finally.

It’s about time they got married. They’ve been living together for five years.

 after all = after everything that happened / despite the facts

This was an expensive car, but I decided to buy it after all.

 all of a sudden = something happens quickly.

All of a sudden, the boy slipped while riding on his skateboard.

 as if = similar; something has a similar quality.

His headache was so bad it felt as if his head was in a vise.

 as soon as = after something happens; immediately after

 Nguyen started to eat his food as soon as it was served to him.

 as well as = and

 She’s strong as well as beautiful.