内摩擦角随颗粒尺寸的加大而减小,随松散物料湿度增加而增加,但()增加到一定限度时,内摩擦角反而下降。
参考答案:湿度
--- ______ Linda often ______ kites in the park in spring?
--- Yes, she often ______ kites with her friends and sometimes they have a picnic together.[ ]
A. Does, fly, flies
B. Do, fly, flies
C. Are, fly, flies
D. Is, fly, flies
给定供应关系SPJ(供应商号,零件号,工程号,数量),查询至少供应了3项工程(包含3项)的供应商,输出其供应商号和供应零件数量的总和,并按供应商号降序排列。
SELECT供应商号,SUM(数量)FROM SPJ
()
();
GROUP BY供应商号
HAVING COUNT(DISTINCT(工程号))>2
A.ORDER BY供应商号DESC
B.GROUP BY供应商号DESC
C.ORDER BY供应商号
D.GROUP BY供应商号