其中正确的有( )
A:1个
B:2个
C:3个
D:4个
下列变化中属于物理变化的是( )
已知△ABC三边长分别为4,4,42,则△ABC的面积为( )
香港和澳门共同的主要经济部门有( )
--- Has he returned the book to our library?
--- No. He has _______ it for several months.