He's not seen his mother for a long time, __________ he?

题干

A：does

B：has

C：doesn't

D：hasn't

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B

A．性质决定用途	B．日常生活经验
氧气助燃﹣﹣气焊切割金属石墨很软﹣﹣制铅笔芯钨的熔点高﹣﹣用于制灯丝	衣服上圆珠笔油﹣﹣用汽油搓洗区别硬水和软水﹣﹣用肥皂水检验区别棉和羊毛织物﹣﹣点燃闻气味
C．化学与健康	D．安全常识
缺钙﹣﹣导致佝偻病或骨质疏松缺碘﹣﹣引起甲状腺肿大缺维生素C﹣﹣引起坏血病	皮肤沾上浓硫酸﹣﹣用氢氧化钠溶液中和炒菜时油锅着火﹣﹣用锅盖盖灭甲醛溶液浸泡海产品﹣﹣保鲜