未知题型 数量遗传学家高尔登比较了男大学生和他们父亲的身高，得到以下结果： 所有父亲的平均身高与所有儿子的平均身高一致，但是对每一对父子而言，两人身高所属的类别(如较高或较矮)却并不一定一致。也就是说，最高的父亲可能有较矮的儿子，而很矮的父亲则可能有较高的儿子。由此得到的最优直线的斜率是0．67(实线)，而不是1．00(虚线)。高尔 登用“回归”(regression)一词来描述这种趋势，即儿子的表型比其父亲的表型更接近群体平均值。 (1)对回归现象作出解释。 (2)在此，回归与遗传率有什么关系?

单项选择题 London's First Light Rail System The Docklands Light Railway (DLR) took just three years to build at a cost of ￡77 million. It is London's first Light Rail System, but its route follows that of a number of older lines, which carried the nineteenth century railways through the crowded districts of the East End.The section of the line from the Tower Gateway Station to Poplar follows the line of one of London's earliest railways, the London & Blackwell (1840), a cable-drawn railway (later converted to steam) which carried passengers to steam ships at Blackwell Pier, and provided transport for the messengers and clerks who went backwards and forwards between the docks (码头) and the city every day.From Poplar to Island Gardens, a new line crosses high above the dock waters, and then joins the old track of the Millwall Extension Railway, built to service the Millwall Docks (1868) and to provide transport for workers in the local factories. This line was horse-drawn for part of its route, until the 1880s.The Poplar to Stratford section of the DLR route was first developed by the North London Railway, built in the 1850s to link the West and East India Docks with the manufacturing districts of the Midlands and North of England. There were major railway works and sidings (分线) at Bow until recently.The trains are automatically controlled from a central computer, which deals with all signaling and other safety factors, as well as adjusting speeds to keep within the timetable; on board each vehicle, Train Captains, who are also fully qualified drivers, are equipped with two-way radios to maintain contact with central control. There are passenger lifts, and self-service ticket machines, at every station. 第 41 题 The passage tells us that London's first Light Rail SystemA．was constructed in the nineteenth century.B．will be finished in three years' time.C．follows some of the original lines.D．took three years longer than expected to complete.

未知题型 一本有关智商遗传率的书做了下列三个陈述。请判断作者关于对H2和h2的各个陈述的正确性，并说明你对H2和h2的理解。 (1)“令人感兴趣的是……‘有怎样的可遗传性?’。(0．01)与(0．99)这两种答案在理论上与实际应用上具有完全不同的含义。”(关于H2的陈述。) (2)“根据经验，在讨论教育时，H2通常是更为相关的参数；而讨论优生学和劣生学时，h2则通常是被关注的焦点。” (3)“但是遗传能力的不同是否来自于基因的差异……这个问题与评估雇佣过程中的歧视情况无关，长远来看，而是可能与决定通过什么方式来改变这种状况有关。”