发电机的定子铁芯为什么不用整块硅钢做成，而要用硅钢片叠装而成？

常青乡村民张三和李四合伙购买了一辆客车，聘请司机王五驾驶，从事本乡与白龙乡之间的客运经营活动。由于李四和张三没有营运执照，就将该车挂靠在乡里的集体企业鸿运客运中心，以该客运中心的名义经营。一日，由于雨后路滑，客车在途中发生车祸，导致车上15名乘客均受了伤，只是各人轻重程度不同。车祸发生后，乘客们被路人送到医院接受治疗，治疗的费用由乘客各自支付。乘客之一的钱六决定与所有乘客一同起诉，要求侵权人支付医药费并赔偿损失。有管辖权的法院受理后，对案件进行了审理并作出了判决，上诉期满双方均未上诉。根据以上案情，请回答下列问题：

如果钱六等三人被推选为诉讼代表人，他们的下列诉讼行为中必须经被代表的当事人同意的是：

A．变更诉讼请求

B．承认对方当事人的诉讼请求

C．提起管辖权异议

D．进行和解

Electronics are being recycled in record numbers as more states require it and more companies collect and even pay for discarded items, but the gains come with controversy.

Some environmentalists complain that recycling is not keeping pace with electronics sales. Some say e-waste is being dumped in developing countries, where toxic materials such as lead and mercury can leach from landfills into groundwater.

"It is a success story, but we’d like to see it get more successful" to keep up with the electronics boom, says Janette Petersen of the Environmental Protection Agency (EPA). The amount of recycled items more than doubled from 1999 to 2007, the most recent year for which the EPA has figures. But as a percentage of all electronics, it increased less, from 15% to 18%. "The demand for electronics recycling has been growing," partly because of the switch last year to digital TV, says Jennifer Berry of Earth911. corn, a private group that keeps a database of recyclers. Last year, she says 31% of inquiries involved electronics, primarily TVs, batteries and computers.

Public and private efforts are expanding. Vermont became the 21st state last month to enact a law that requires e-waste recycling. Twenty-six companies--including Dell, Hewlett Packard, AT&T and Verizon--have partnered with the EPA on the Plug-In to eCycling program to promote electronics recycling since its launch in 2003. Companies such as Gazelle. corn pay for used gadgets such as iPods, which they resell or recycle. Best Buy and other stores are collecting more e-waste. Target announced last month that it put bins in every store to accept cellphones, MP3 players and ink cartridges.

Jim Puckett of Basel Action Network, a Seattle-based non-profit organization that aims to stop toxic exports, worries that some American companies dump e-waste in Africa to save money. "People are trying to look green, but they’re not telling you where it (waste) is going," he says. "You can’t turn over your TV to just any recycler. " He says it’s better to store an old TV than give it to a recycler that may export it to poor countries.

The Basel Action Network announced its e-Stewards program last month to ensure safe handling of electronics by using only recyclers certified by accredited organizations. It now lists 45 recyclers in 80 locations. Samsung and other companies have signed on. Environmental groups, including the Sierra Club, back it.

What is the main idea of the text（）

A. Recycling of electronic items is a "success story"

B. Environmentalists are opposed to recycling electronics

C. Recycling can not keep pace with electronics sales

D. It is unnecessary to recycle electronics

某施工项目招标设有标底，其中招标人组织编制的标底为α，所有投标人报价的平均值为β，以标底α值作为确定有效标的标准，以进入有效标内投标人的报价平均值为γ，则评标标底可采用（）。

A.α

B.β

C.γ

D.（β+γ）／2

E.（α+γ）／2

企业发生的支出应当区分收益性支出和资本性支出。收益性支出在发生当期直接扣除，资本性支出不得扣除。

全陪小赵带游客到江西旅行，到达目的地当日却只有旅游大巴来迎接，地陪由于临时有事第二天才能到位。旅行社指示你先带客人玩一天，你该怎么办？