问题
选择题
Most of us think that the ocean bottom is ___ smooth land.
A．made up for
B．made up of
C．made of
D．made by
答案
答案：B
be made up of意思是:由…组成.
搜题请搜索小程序“爱下问搜题”
Most of us think that the ocean bottom is ___ smooth land.
A．made up for
B．made up of
C．made of
D．made by
答案：B
be made up of意思是:由…组成.
矩阵A=E-αTα，B=E+2αTα，其中E为n阶单位矩阵，则AB等于（）。