单选题 The students had a lot of trouble concentrating on their study because of the noise from the construction outside.
  • A. focusing
  • B. carrying out
  • C. paying for
  • D. continuing with


【正确答案】 A
【答案解析】[解析] concentrate和focus同义，集中、专注；carry out：贯彻、执行；pay for：花钱买……；continue with：继续做……。