【单选题】The country has ______people and ______money ______spent on tobacco every year.
A.
a large quantity of, a number of, are
B.
plenty of, a great deal, are
C.
a great deal of, plenty of, is
D.
a large number of, a large amount of, is
【判断题】轴箱装置的作用是将轮对和侧架连接在一起;承受和传递轮对与转向架之间的各种载荷,承受车体重力,传递牵引力、制动力;保护轴颈,使轴颈与轴承间得到润滑,减少摩擦以防止在高速运行条件下发生热轴,保证列车运行安全。
【单选题】如果直接运用OLS法对联立方程组进行估计,则估计值是:()。
【单选题】某校举行 “汉字听写比赛”, 5 个班级代表队的正确答题数如图.这 5 个正确答题数所组成的一组数据的中位数和众数分别是( )
【判断题】在线性回归模型中,如果误差满足零均值、同方差且互不相关,则回归系数的最佳线性无偏估计(BLUE, Best Linear unbiased estimator)就是普通最小二乘法估计。这里不需要假定误差满足独立同分布(iid)或正态分布,而仅需要满足零均值、不相关及同方差这三个稍弱的条件。
【单选题】希腊神话中的著名女巫()掌握着生杀予夺的魔力。
【单选题】转向架是一种能相对车体回转且具有对结构的(),通常安置在车底架两端的下方,用以承载车体重量和传递走行动力。
【单选题】Unacceptably large quantities of impurities are left in the oil after the purifying process. which cause is incorrect?
A.
The oil is insuffciently heated.
B.
The throughput is too high
C.
The wrong type of gravity disc is fitted
D.
The density of impurities is too large.