This problem can be solved intuitively.

This area is still in a developing stage.

He is suitable for the job.

He is devising a strategy against the enemy nation.

He is interested in the high-tech industry.

He made no attempt to hide his hostility towards me.

The police exposed the fraudulent behavior.

The police exposed the illegal transaction.

I dropped a few drops of vanilla essence into the cake mix.

Please add an appropriate amount of salt according to the recipe.