--Where is my watch? I ________ find it.
--Don't worry. It must be somewhere in your room.
A:can't
B:mustn't
C:needn't
D:shouldn't
如图,△ABC中BC边上的高为h1,AB边上的高为h2,△DEF中DE边上的高为h3,下列结论正确的是( )
经过点A(1,0),B(0,﹣1)的直线方程为( )
下列关于修建亚马孙横贯公路的说法不正确的是( )