【单选题】About Database, which of the following is WRONG?
A.
Relational model is an obsolete database model now
B.
DBMS means database-management system.
C.
A query is a request to see information from a database that matches specific criteria
D.
A record is a collection of related fields in a database and also called a row
【单选题】一些成年人体内( )活性过低,大量食用乳及乳制品可能引起乳糖不耐受的发生。
【单选题】一些成年人体内( )活性过低,大量食用乳及其制品可能引起乳糖不耐受的发生
【简答题】(1)化简: sin( π 2 +α)?cos( π 2 -α) cos(π-α) + sin(π-α)?sin(-α) sin(π+α) ; (2)设两个非零向量 e 1 和 e 2 不共线,且 AB = e 1 +2 e 2 , BC =-2 e 1 +3 e 2 , CD =5 e 1 +3 e 2 ,求证:A,B,D三点在同一直线上.
【单选题】已知函数f(x)=-cosx+e x ,则f′(1)的值为( )
【单选题】I would rather apologize to my boss for being late without an explanation than ______ an excuse.
【单选题】一些成年人体内()活性过低,大量食用乳及其制品可能引起乳糖不耐受的发生