单项选择题
From paragraph 1, we know that some 40 genes involving in cancer are （）
A．harmful to the human body B．necessary to the human body C．the elements that form cancer D．useless to the human body
单项选择题 21（）
单项选择题 --What do you think of his ______ play --I like it much-better than his ______ one.
填空题 A．pass B．paste C．lady D．lake
