Mr. Green is very happy because he is satisfied with his students' work today.
A:is moved by
B:is good for
C:is fond of
D:is pleased with
如图,半圆O的直径AB=4,与半圆O内切的小圆O1,与AB切于点M,设⊙O1的半径为y,AM=x,则y关于x的函数关系式是( )
根据图片提示补全单词:bo____