地面无矿物加工的矿井生产系统，包括有()环节。A.井口设施  B.井口筛选、破碎

A公司的职能部门与B公司订立保证合同为C公司提供担保，但是B公司并不知道与其签订保证合同的是A公司的职能部门，后因纠纷诉至人民法院，法院判决该保证合同无效，导致B公司发生了损失，根据规定，下列选项中正确的是()。

A．由A公司向B公司承担民事责任

B．由A公司的职能部门向B公司承担民事责任

C．由A公司及其职能部门共同向B公司承担民事责任

D．由A公司和B公司根据其过错各自承担相应的民事责任

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STEVE Wayne, 16, who worked this summer as a lifeguard and swim teacher in Idaho Falls, was thrilled to see an extra $20 in his paycheck when the federal minimum wage increased in July.

“When you’re getting paid minimum wage, anything helps, ” Wayne said.Wayne is one of several hundred thousand American teenagers who earn the minimum wage. The last of three recent increases that took the minimum from $5.15 an hour in 2007 to $7.25.U.S. Secretary of Labor Hilda Solis says the minimum-wage increase will pump an extra $5.5 billion into the economy over the next year, which is helpful at a time when the economy is hurting.

"You're giving people who spend money a raise," says Kai Filion of the Economic Policy Institute. "Those people will go out and spend that money, and it will circulate through the economy."

But other economists say raising the minimum wage actually hurts the very people it's designed to help. A higher hourly minimum, they say, could force businesses to cut workers' hours, or even lay people off.

"What matters for people earning minimum wage is how much money they take home, in total, in their paycheck," explains Rajeev of Georgia State University's Economic Forecasting Center. "Their hourly rate may go up, but their number of hours may come down, so it's not an overall increase."

Business owners also say that raising the minimum wage exerts（施加）upward pressure on other wages. "If the minimum wage is $7 and I have to pay $8 or $9 to hire a dishwasher, then the cooks are going to say they want more," sayd Cleveland restaurant owner Rick. "How much can I charge for that hamburger?"

Another argument is that it makes it more expensive for businesses to hire new workers. For many businesses already struggling to make ends meet in these tough times, it will be simply too expensive to keep or to hire new people.

55．Steve Wayne was excited that_____________ .

A．his hard work had paid off

B．he had received a big wage increase

C．he has more money due to an increase in minimum wage

D．the wages of American teenage workers have been increased

56．According to the text, the US federal government has increased minimum wage with the aim of__________

A．decreasing unemployment

B．promoting economic recovery

C．increasing American teenagers’ wage

D．narrowing the gap between the rich and the poor

57．What matters most to people in need of help is_____________.

A．a higher hourly minimum       B．more working hours

C．a minimum-wage increase      D．an increase in total income

58．Some are against the increase in minimum wage because they say_____________.

A．only very few workers will be helped

B．they have to cut down working hours

C．many business owners can’t afford to employ new workers

D．minimum wage workers will expect more pay rises in the future

物体C置于水平地面上，A、B由细绳通过固定在C上的定滑轮相连，C的上表面水平，整个系统处于静止状态，不计滑轮与细绳之间的摩擦，则下列说法正确的是（　　）

A．B与C之间的接触面一定是粗糙的

B．B与C之间的接触面可能是光滑的

C．C与地面之间的接触面一定是粗糙的

D．C与地面之间的接触面可能是光滑的

三相电网对地产生零序电压，说明一相绝缘损坏。（）

发动机供给系由（）等组成

A、汽油箱

B、汽油泵

C、空气滤清器

D、汽油滤清器