—Oh, my God! It's a gift(礼物) for James. I forgot ______ it this afternoon.
A:to post
B:posting
C:post
D:posts
如图,矩形ABCD中,AD=2,AB=5,P为CD边上的动点,当△ADP与△BCP相似时,DP=____ .
下列关于生物群落的叙述,错误的是( )