第26题: [单项选择]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 参考答案: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……。
第27题:[单选题]可见光的波长范围为( )。 A. A、340nm至760nm B.B、370nm至760nm C.C、380nm至760nm D.D、300nm至760nm 参考答案:C