It's rather windy today. Put on some warm clothes, _________ you'll catch a cold.
A:and
B:but
C:or
D:so
如图,两张宽为1cm的矩形纸条交叉叠放,其中重叠部分是四边形ABCD,已知∠BAD=60゜,则重叠部分的面积是____cm2.