| 1 | He cast about desperately for something tosay. | |
| 2 | She racked her poor brains to have the laugh on me. | |
| 3 | The so - called poet ground out some verses. | |
| 4 | We'll have to rack our brain and think of some effective measures. | |
| 5 | He had racked his brain, but hadnrt been able to work out the answer to the problem. |