鲫鱼、虾、蚌、蟹都生活在水中，若将它们分成两类，其依据是（　　）

    I'm Sam. My hobby is playing chess（棋）—one of the greatest games in the world. My mom taught me how to play when I was 7. She beat (打败) me every time for the first year. But then on my eighth birthday, I won for the first time. I nearly always beat her from then on.

    It takes about a day to learn the rules (规则). But if you want to be good, you have to practice for years. You don't need much to play chess—just a chess set (棋具) and someone to play with.

    Chess sets can be quite cheap, or very expensive. Some people collect chess sets as a hobby, but some prefers playing.

    There is a chess club in our school, and we meet every week to play with each other. I'm the best player in the club, and the captain of the school chess team. This year we won the All English Schools' Championship (锦标赛), and I had to go up on stage (台子) in front of the whole school to accept the trophy (奖品).

    I'm saving up my money to buy a chess computer. It's very expensive, but very good for practice. In that way, I'll always have someone to play with. One day I will be the world chess champion (冠军).

关于人的生殖细胞中性染色体的叙述，正确的是（    ）

将下列陈述句改成反问句

①最使我着迷的还是绿叶。

②那真是令人愉快的活动。