The baby feels________while his mother holds him in her arms．

—What do you think of the environment here？
—Wonderful！________of the land________covered with trees and grass．

—Jack，I have________working out the math problem．
—Don’t worry．Let me help you．
A．fun
B．trouble
C．experience

Our teachers are very friendly to us．We________friends since three years ago．
A．have been
B．have become
C．would be

（安徽）As we all know，the Silk Road________China to the West in ancient times．