下列命题中,不正确的是[ ]
A、对角线互相平分的四边形是平行四边形
B、对角线相等的四边形是梯形
C、对角线相等且平分的四边形是矩形
D、对角线互相垂直且平分的四边形是菱形
答案:B
广州市小学数学奥林匹克业余学校入学考试,试题有10道选择题,答对一题得4分,不答或答错得0分;还有10道简答题,答对一题得6分,不答或答错得0分.问试卷成绩最多有______种不同的分数.
We arrived at work in the morning and found that somebody ______ into the office during the night.
A. broke B. had broken C. has broken D. was breaking