下列不是联合国安全理事会常任理事国的是（  ）

C

    Shopping on the Internet is becoming more and more popular. Why do people use the Internet to shop? Some people say it is more convenient. They don't have to leave their homes to order something;    ①   ; they can find things for sale that they can't find in the stores near their homes.  ②   .

    If you want to buy something on the Internet, you need a credit(信用) card. You have to type your credit card number and information on the website and send them to the store over the Internet. You have to be sure that the store will not use your information in the wrong way. You don't want someone to get your credit card number, so be careful with it, because people sometimes steal credit card numbers from stores.

    The Internet is also a good place to go window-shopping. Window-shopping is when you look at the things for sale in a store, but don't plan to buy anything. In window-shopping you can see what kinds of things you are able to get and how much they cost. Some stores like Ross Stores have a website for information about their stores, but not for shopping. Some stores have a website for information about their stores, and can shop on-line there, such as Office Depot, Payless Shoe Source, Safeway. Some stores like Amazon. com are only for on-line shopping.

张华和同学到游子山参加社会实践活动，拾到一些不规则小石块，他们很想知道这种小石块是什么材料做成的，就把它们带回学校利用天平和量筒来测定这种小石块的密度。