在完成高锰酸钾制氧气的实验后，胜涛同学总结了以下注意事项，其中不正确的是（）
①药品要堆积在试管底部；②试管口要略向下倾斜；③铁架台铁夹夹在试管的中上部(或距离试管口的1／3～1／4处)；④试管口要放一团棉花；⑤试管外壁要干燥；⑥加热时，先将试管均匀受热，然后用酒精灯外焰固定对准药品加热；⑦用排水法收集要等导管口有均匀的气泡冒出时，再收集；⑧实验结束时要先将导管从水中取出再熄灭酒精灯；⑨盛氧气的集气瓶要盖上玻璃片、正放。

阅读下面短文，根据短文内容判断句子的正误。

    More and more advertisements appear on the Web. You have to be careful not to be fooled or tricked(欺骗) by the advertisements on the Internet. Something is said to be a bargain(便宜物品), but it isn't always cheap. And some so-called new things just have a new outside.

    However, shopping online is a kind of fashionable(时尚的) thing today. I love to buy things of everyday use, so I often get lots of information about them on websites online. For example, if I want an MP3, I can choose my favorite one, and look for what the users like or don't like about it, then decide whether to buy or not. And at the same time, you don't have to go to a shop or walk around a crowded shopping area, so you don't have to waste much time. The Internet is really useful for shopping, but be careful not to spend too much.