一、单项选择（共15题计分15）
21.He has _______ advantage of Tom in maths but he often takes _______ advantage of Tom in the exam.
A.an ,the B.the,an C.an,/ D.the,/
22.The teacher spoke so fast that none of his students could really understand _______ he said meant.
A.that B.what C.what what D.that that
