What are the features of columns?（ ） A: Columns are usually characterized by fixed names and locations. B: Columns are printed pages where manuscripts of certain contents are published. C: Columns are relatively independent in the overall layout of newspapers and periodicals. D: Articles in columns are of various styles.

对均相反应:aA+bB=gG+hH,下列关系中正确的是:() A: -dcA/dt=-dcB/dt=dcG/dt=dcH/dt B: (1/a-dcA/dt)=(1/b-dcB/dt)=(1/gdcG/dt)=(1/hdcH/dt) C: a(-dcA/dt)=b(-dcB/dt)=g(dcG/dt)=h(dcH/dt) D: g(-dcA/dt)=(ag/b-dcB/dt)=a(dcG/dt)=(ag/hdcH/dt) E: (a/g-dcA/dt)=(b/g-dcB/dt)=dcG/dt=(g/hdcH/dt)

If a is known to be a 2×3 matrix, then after executing a=a(:), ( ). A: a transforms to a column vector B: a transforms to 3 rows and 2 columns C: a transforms to 3 rows and 3 columns D: a transforms to 2 rows 3 and columns

dt为DataTable类型的变量，引用名为"Customers"的DataTable对象。该表中包含"CustomerID"、"CustomerName"、"Address"、"Telephone"等4列。将数据列"CustomerID"设为该表的主键的正确语句有：（） A: dt.PrimaryKey="CustomerID"； B: dt.PrimaryKey.Add（"CustomerID"）； C: dt.PrimaryKey=newobject[]{"CustomerID"}； D: dt.PrimaryKey=newDataColumn[]{dt.Columns["CustomerID"]}；

在总量生产函数Y=AK^α L^(1-α)设定下，新结构经济学假设生产函数随时间可变，那么索罗剩余（A）的增长率为（）。? (dA/dt)/A=(dY/dt)/Y-α (dK/dt)/K-(1-α); (dL/dt)/L-ln⁡(K/L)dα/dt|(dA/dt)/A=(dY/dt)/Y-α (dK/dt)/K-(1-α)(dL/dt)/L|(dA/dt)/A=(dY/dt)/Y-α (dK/dt)/K-(1-α); (dL/dt)/L-lnK×dα/dt|(dA/dt)/A=(dY/dt)/Y-α (dK/dt)/K-(1-α); (dL/dt)/L-lnL×dα/dt

Which of the following are the types of columns encountered in gas chromatography?(1) flat plates (2) packed columns (3) plastic strips (4) open tubular, or capillary columns A: 1,2 B: 3, 4 C: 1, 3 D: 2,4

The Greek orders of columns are used including

The product of two matrices ,AB is defined. Then each column of AB is a linear combination of the columns of B using weights from the corresponding columns of A.

If it is known that A is a 3×5 matrix, after executing A(:,1:2:3)=[], ( ). A: A becomes row vector B: A becomes 3 rows and 3 columns C: A becomes 3 rows and 2 columns D: A becomes 2 rows and 3 columns

DT服务交付不包括（） A: sitesurvey  B: DT准备  C: DT测量  D: DT后处理