下列判断正确的是（ ）
A．平角是一条直线
B．凡是直角都相等
C．两个锐角的和一定是锐角
D．角的大小与两条边的长短有关
答案：B
此题考查命题的正确与否的判断和角的有关概念；直角都是90°的角，所以都相等，所以B正确；角是有公共点的两条射线所组成的图形，所以A错误；两个锐角的和可以是直角，所以C错误；角的大小与角的两边张开合拢的程度有关，和边的长短无关，所以D错误，选B；
用方框中所给单词的适当形式填空，使短文通顺、正确、连贯(每个单词限用一次)。
As the afternoon was hot. I did my work in the morning. I 63 to get up at 6:30 and take a walk in the garden for half an hour. After breakfast, I began reading English and Chinese and did some 64 in math, It took me three hours or65 . I worked quite 66and made good progress. I spent the afternoon outside. I went to swim and it was 67 . I would not go home until it was about five or six o’clock. Sometimes a friend of mine would come to see me and we would spend some hours 68 to music. In this way I spent my vacation slowly. And I not only studied well but also became a good 69 . now I am in good 70 and high spirits. |