I am tired of his constant woolgathering — I wish he would concentrate on his work.我真受不了他老是那样心不在焉，希望他集中心思工作。He could hardly keep his mind on what she was saying.他无法集中心思听她说话。It's amazing how much work you can do in a day if you put your mind to it.如果你集中心思，那么一天内你能完成的工作量是惊人的。