一片青草地，每天都匀速长出青草，这片草地可供27头牛吃6周或23头牛吃9周，那么这片草地可供21头牛吃（　　）周．

当你吃了不洁食物导致腹泻时，你应该选择服用下列药物中的（   ）

阅读下列有关明清时期徽商的材料，回答问题。

材料一新都(新安)，勤俭甲天下，故富亦甲天下。贾人娶妇数月，则出外或数十年，至有父子邂逅而不相识者。大贾辄数十万，则有副手而助耳目者数人。其人皆铢亮不私，故能以身得幸于大贾无疑，他日计子母息，大羡，副者始分身自为贾。

——顾炎武《肇域志·徽州府》

材料二徽郡商业，盐、茶、木、质铺(典当业)四者为大宗。茶叶六县皆产，木则婺源(地名)为盛，店铺几遍郡国，而盐商成萃于淮、浙。

——陈去病《五石脂》

材料三江南各地的徽杭大贾，不仅贩布，而且染布、踹布(将布踹压平整使其紧薄有光)；不仅贸丝，而且开车缫丝。

——翦伯赞主编《中国史纲要》

材料四大抵徽俗，人十三(十分之三)在邑，十七在天下；其所积蓄，则十一在内，十九在外。

——王世贞《四部稿》

求：

       These days computer games have bcome more and more popular in many cities and towns. A lot of small shops along busy 1have changed into computer game houses in order to get more 2. These places are always crowded with people
       In the computer game houses, people 3a lot of money matching on the machine. It's4for one to beat a computer, but one can do well after trying again and again. People want to5 when they play computer games. The more they6, the more they want to win, and at last they even can't 7without it.
       The result is that some people don’t want to8and they play in computer game houses for hours and hours. For school boys, things are 9. They don't want to have10. When school is over, they rush to the computer houses near their 11. Some of them can get enough money from their 12 Some of them are not13to get the money. So they have to steal or rob others' and become14 . Computer game addiction(上瘾) is a 15problem in our life. Something has to be done to stop it.