Mr. King ____ (hold) a party to celebrate his mother's eightieth birthday next week, isn't he?
若E为CD的中点,正方形ABCD的边长为4,求DH的长.
小明沿着坡比为1:3的山坡向上走了600m,则他升高了( )
将下面的两个小平行四边形,拼成一个大平行四边形,有两种拼法.