炼丹术中的几种主要矿物是什么？

在船舶接收到HF上DSC遇险报警后，如不能进行救助，船舶正确的操作有（）。①立即收妥；②在RT或NBDP遇险频率上收听5min，等待遇险收妥；③马上转发；④收听是否有遇险通信；⑤在无收妥和无遇险通信的情况下进行HF遇险转发；⑥通知RCC

A.②③④⑥

B.①④⑤⑥

C.②④⑤⑥

D.①②④⑥

关于理财产品申购，正确的有（）。

A.理财产品认购、申购必须达到最低起点金额

B.如果理财产品设有单笔认购、申购上限，认购、申购金额不应高于认购、申购上限

C.认购、申购客户必须在中国农业银行开立结算账户

D.理财产品在认购、申购交易前需确定投资者的风险属性，并进行产品适合度评估

E.原则上客户认购、申购后不允许撤销交易

Harvard University, breaking with a major trend in college admissions, will eliminate its early admissions program next year, with university officials arguing that such programs put low-income and minority applicants at a distinct disadvantage in the competition to get into selective universities.
For three decades Harvard has offered a particular form of early admissions, in which students who are accepted early still have the freedom to go elsewhere. Various forms of early admissions are offered by hundreds of colleges and universities, with many requiring applicants to commit upfront(预先) to attending the university if offered early admission.
The popularity of the procedure grew significantly in the 1990s, as colleges tried to increase their competitive advantage by locking in p candidates early. But at Harvard and many other universities officials have grown concerned about that early admissions present a major obstacle to low-income and working-class students. Such students have also been hurt by steep tuition increases and competition with students from wealthy families who pour thousands of dollars into college consultants and tutoring.
Under binding early admission programs, students have to commit to a college long before they know how much aid they will be offered; whereas students who apply for admission ill the regular cycle are able to compare financial-aid offerings from various colleges before making up their minds in April. Under Harvard’s early admissions program, students do not have to decide until May 1 whether to accept an admission offer. Even so, many potential applicants did not understand the distinction between Harvard’s program and those that require an upfront commitment and were discouraged from applying.
Under Lawrence H.Summers, the Harvard president who left office in June, the university took a number of steps to make itself more accessible to poor and working-class students. The idea of abandoning early admission was developed after Derek Bok became interim president. Early admission will remain in effect in the current academic year, which is already under way.

The procedure of early admission grew popular because it helped colleges to secure the recruitment of ______.

在四行程发动机中，曲轴旋转两圈各缸工作一次。

亚洲有一种毛竹，最初5年里在地下生根长达几千米，人们几乎看不到它的生长。第6年雨季到来时，它钻进地面，以每天60厘米的速度涨到30米高。下列选项与其所含哲理一致的有（）

①人生譬如滑雪，只有知道如何停止的人才知道如何加快速度

②旋岚偃岳而常静，江河竞注而不流，野马飘鼓而不动，日月历天而不周

③飞花两岸照船红，百里榆堤半日风。卧看满天云不动，不知云与我俱东

④逝者如斯夫，不舍昼夜

A.①④

B.①③

C.②③

D.③④