题目

一束光线从左边入射到水平放置的平面镜，当入射光线与平面镜成40°角，则反射角是度，若入射光的位置不变，让平面镜沿竖直方向顺时针转过10°，则反射光线与入射线夹角为度． 答案：【1】50【2】120In England , afternoon tea is the most informal (非正式）meal of a day .It is taken between four and five. If you are a friend of the family, you may come for tea at any time. Very often it is not taken at a table. The members of the family and visitors take the tea in the sitting room. Each person has a cup and saucer (茶盘), a spoon (调羹) and a small plate for bread and butter (黄油) and cakes. By the way, do not help yourself to cakes first, bread and butter first, and then cake. Do remember: Though you can eat as much as you want, do not put more than（超过） one piece of bread or cake on your plate each time.【小题1】In England, afternoon tea is usually taken ________ . A．between breakfast and lunch　　 B．in the middle of day C．early in the afternoon D．late in the afternoon 【小题2】A real English afternoon tea has___________.A．tea only B．both tea and food C．tea food and vegetables D．the same things as other meals 【小题3】If you want to have afternoon tea in a friend's home, _______________.　A．you must send a message before you go B．you must take food with you C．you may go only when you're asked to D．you may go at any time 【小题4】Help yourself to ______________. A．cake first B．bread-and-butter first C．either bread first or cake first D．only one piece of bread or cake 【小题5】Which of the following is NOT true? A．People don't use the same spoon for afternoon tea. B．Afternoon tea is often taken in the sitting room. C．For afternoon tea, people use cups only. D．Afternoon tea is often taken with bread and cake.