Lucy likes English very much . She does her best _____it well.
A：to learn
B：learn
C：learning
D：is learning
“中华开国五千年,神州轩辕自古传,创造指南车,平定蚩尤乱。”文中“轩辕”指的是( )
解决我国水资源短缺问题的根本出路是（ ）
