单项选择题
I wrote to Mr. Green, ______ him ______ the lost case.
单项选择题 Our national scenery Zhangjiajie is so charming that it is ______ description.
单项选择题 The diligent student refused the help of others and insisted on working out the difficult maths problem ______.
单项选择题 The old man took the boy ______ the hand and walked away.
