| A | B |
| decrease | to become less or go down to a lower level, or to make something do this |
| essential | extremely important and necessary |
| improve | to make something better, or to become better |
| necessary | what you need to have or need to do |
| reduce | to make something smaller or less in size, amount, or price |
| research | serious study of a subject, in order to discover new facts or test new ideas |
| strength | the physical power and energy that makes someone strong |
| study | when you spend time learning, especially at home or by yourself rather than during school |