When Jack was very young, he often played football, and he was very  1  at it. But then he went and worked in a town and there was no   2 for him there, so he stopped  3 .

Then he began to get rather  4  . So he thought ,“I’ve stopped playing football, and now I’m getting fat.  5   am I going to do?” He thought about it for  6 , and then he said to himself, “I know , I’ll play tennis .”

He had a few   7 , and then played for a few months. He met a nice girl at the tennis club one day, and they played a game of tennis   8 another young man and woman. Jack played very badly and was very   9 with himself .“I’ve never played as badly as this before, ” he said to the girl.

“ Oh,” she said , “you   10  how to play tennis ?”

通过（）手段，我们可以判断农产品中是否有农药残留。

A、肉眼观察

B、嗅觉感受

C、送专业实验室检测