【单选题】已知直线l:xtanα-y-3tanβ=0的斜率为2,在y轴上的截距为1,则tan(a+β)=( )
【单选题】招标人和中标人应当在中标通知书发出( )日内,按照招标文件和中标人的投标文件订立书面合同。
【单选题】To assess how well a student is performing relative to his or her own previous performance,a teacher would use_________ assessment.
【单选题】下面四组移出断面图中正确的是 ( ) 。
【单选题】下图中,指向高压压气机的标号是: 【图片】
【单选题】What is the main idea of the second paragraph?
A.
Some plants have relative immunity to a great many diseases, while others have a susceptibility to them.
B.
The tolerance of a particular plant changes as the growing conditions change.
C.
A blight killed virtually every chestnut tree in North American.
D.
A blight may be a national infection.
【简答题】招标人和中标人应当在中标通知书发出( )13内,按照招标文件和中标人的投标文件订立书面合同。