The depletion of soil nutrients due to monocropping is becoming a problem.

It is difficult to find the optimal solution to this problem.

He is the weakest member of the team.

He squeezed a lemon to make fresh lemon juice.

Yesterday, I went to see a movie.

He always acts first.

He didn't notice the error in the calculation.

He misunderstood my intentions.

This policy is necessary to stimulate the economy.

The stricture in his heart is causing a serious problem.