方程x2+x-m7=0的两根之积等于两根之和，则m的值为______．

下列选项中，体现中 * * 伟大民族精神的是[ ]

①人不为己，天诛地灭

②先天下之忧而忧，后天下之乐而乐

③天下兴亡，匹夫有责

④富贵不能淫，贫贱不能移，威武不能屈

A．①③④

B．①②③

C．①②④

D．②③④

Ship tourism to Antarctica is on the rise: More than 35,000 tourists are expected to visit Antarctic this summer. In 1992-1993, 6,750 visited Antarctica, according to the Antarctica Treaty. All of this tourism, however, is putting both tourists and the environment in great danger.

Among the tourist ships that visit the continent, the Explorer, a Canadian ship, was one of the first. Put to use in 1969, it was built to carry tourists to Antarctica. Last week, however, it became the first commercial passenger ship to sink beneath the waters. Fortunately, all of the passengers and crew members were rescued from the ship. However, the sunken ship endangered the Antarctic’s fragile(脆弱的) environment. The ship was estimated to be holding 48,000 gallons of fuel.

The accident was not unexpected. Both the US and UK had warned a conference of the Antarctic Treaty member countries in May that the tourism situation in this area was a potential disaster. The US said in a paper, people “should take a hard look at tourism issues now, especially those related to ship safety.” Although the Antarctic seas are relatively(相对地) calm, floating ice causes a potential threat to ships. The owner of the Explorer blamed the sinking on a fist-like hole in the ship created by ice.

Many of the other large ships now visiting Antarctica are not designed especially against thick ice. Such ships generally can only come to the continent in summer. But the tourist rush is pushing ships into dangerous situations. “The increasing number of ships operating in Antarctic means that the ship are under great pressure to get there in time for the key visiting sites,” the British government wrote in a paper at the meeting of member countries.

As a natural frontier, Antarctica is in a messy legal situation. There are no obvious answers as to who is responsible for dealing with the threat that tourist may cause to human life and the environment.

There is no coast guard for Antarctica. Do we want it to become Disneyland, or do we need some controls?

76. Which of the following is true according to this passage?

A. Antarctica tourism has a history of about 17 years

B. The number of tourists to the Antarctic is over 5 times as large as that of 17 years ago.

C. The tourism boom has caused holes in the floating ice in the Antarctic.

D. The Antarctica Treaty is responsible for the problem.

77. The sinking of the Explorer____________.

A. led to a conference about the tourism situation in the Antarctic.

B. was caused by the rough seas

C. had been predicted

D. did harm to the Antarctic.

78. It can be inferred from the passage that_________.

A. a Disneyland will be built in the Antarctic

B. fewer people are visiting the Antarctic because of the warnings given

C. not all the ships are suitable to go to the Antarctic

D. some ships take risks visiting the Antarctic in other seasons rather than in summer

79. In this passage, the writer suggests that___________.

A. people had better not make a tour of the Antarctic

B. ships to the Antarctic should be built strong enough

C. there should be legal controls over tourism in the Antarctic

D. the Antarctic’s environment is fragile

80. What attitude does the writer hold towards Antarctic tourism?

A. Supportive.     B. Positive.       C. Indifferent.        D. Anxious.

起吊重物时，当吊钩处于作业位置最低点时，卷筒上缠绕的钢丝绳，除固定绳尾的圈数外，放出钢丝绳时，卷筒上应至少保留（）圈；当吊钩处于作业位置最高点时，卷筒上还宜留有至少1整圈的绕绳余量。

A.1

B.2

C.3

D.4

机车运行前，对没有加装重联装置的无动力回送机车，两端自动制动阀手柄要置于手柄取出位；并取出手柄；两端单独制动阀手柄均置运转位；开放无动力装置塞门；分配阀的常用限压法的限制压力调整到场250Kpa；连接两端列车管，并开放折角塞门。

某城市轻轨工程的建设单位自行办理招标事宜。由于该工程技术复杂，建设单位决定采用邀请招标，共邀请A、B、C三家国有特级施工企业参加投标。
投标邀请书规定：6月1日～6月3日9:00～17:00在该单位总经济师室出售招标文件。
招标文件中规定：6月30目为投标截止日；投标有效期到7月20日为止；投标保证金统一定为100万元，投标保证金有效期到8月20日；评标采用综合评价法，技术标和商务标各占50%。
在评标过程中，鉴于各投标人的技术方案大同小异，建设单位决定将评标方法改为经评审的最低投标价法。评标委员会根据修改后的评标方法，确定的评标结果排名川页序为A公司、C公司、B公司。建设单位于7月15日确定A公司中标，于7月16日向A公司发出中标通知书，并于7月18日与A公司签订了合同。在签订合同过程中，经审查，A公司所选择的设备安装分包单位不符合要求，建设单位遂指定国有一级安装企业D公司作为A公司的分包单位。建设单位于7月28日将中标结果通知了B、C两家公司，并将投标保证金退还给该两家公司。建设单位于7月31日向当地招标投标管理部门提交了该工程招标投标情况的书面报告。

问题

该建设单位在招标工作中有哪些不妥之处请逐一说明理由。