【简答题】通常把______的透镜叫凸透镜,凸透镜对光线有______作用;把______的透镜叫凹透镜,凹透镜对光线有______作用.
【单选题】关于透镜,下列说法中正确的是( )
A.
凸透镜和凹透镜都有焦点,凸透镜有实焦点,凹透镜有虚焦点
B.
凸透镜对光有会聚作用,因此通过凸透镜的光都一定会聚在焦点
【单选题】Either your teacher or you ______ mistaken.
【简答题】Although he is o____-looking, yet he is well received by his workmates.
【单选题】Mr. Smith works with an auto company, but he _________ for this industrial exhibition, since he is on leave. [ ]
【简答题】根据首字母或汉意填空,每空一词。 1. Zhu used to be shy, but now he is o______. 2. I don't like speeches. I feel n______ talking in front of many people. 3. When I began to sing,he laughed and made me very ____...
【单选题】Either you or your teacher _________ mistaken.