（21） buying and selling products, e-business may also（22） other traditional business aspects. The use of electronic chat as a form of technical and customer support is an excellent （23） of this. An e-business which uses chat to supplement （补充） its traditional phone support finds a system which （24） incredible amounts of time while providing opportunities （25） through traditional support. By using （26） computer systems, for example, technical support operators can remotely （27） a customer's computer and （28） them in correcting a （29） . And with the download of a small program, all pertinent information about the hardware and software specifications for a user's computer may be relayed to the support operator directly, without having to walk a customer through personally （30） the data.
21.
A、Beside
B、In addtion
C、In addtion to
D、As well
【正确答案】：C
【题目解析】：beside在旁边；In addtion此外，另外，后面常用逗号隔开；In addtion to除了，其后接名词短语；as well也。根据句意这里应该是说除了买卖产品，故选C。
