I usually go to school by bike, today I took a bus because it rained heavily.
A:but
B:so
C:if
D:or
面值20元和50元人民币上(图中)景观所在地区主要的少数民族分别是( )
I don't know ________.
我国东北平原盛产的农作物有( )
①相等的角是对顶角;
②如果三角形中有一个角是钝角,那么另外两个角为锐角;
③若两直线平行,则内错角相等;
④若x>0,则|x|=x.
其中是真命题的有几个( )