正确答案: D

表示某随机样本的抽样误差

题目：Sx表示的是（ ）。

解析：D

查看原题

举一反三的答案和解析：

[单选题]When your colleague brings about a problem, you should _______ .

find a better way to handle the problem

解析：

由第二段if your colleague causes you problems on the job for lack of responsibility or ability, find ways of dealing with his irresponsibility or inability rather than simply blame the person.可知

[单选题]关于主动转运的叙述错误的是（ ）。

只要药物浓度增加，吸收速度就会相应增加

[单选题]

B．Because C．Until D．So

AsB．Because

[单选题]具有漏斗形花冠的分类群是( )。

旋花科

[单选题]The school rules state that no child shall be allowed out of the school during the day, ______ accompanied by an adult.

unless

解析：本题考查省略的状语从句的连接词。句意应为“学校规章规定：除非有成年人陪同，否则孩子们在校期间不能出学校。”表示“除非”用unless。该句式构成了“连词+过去分词”结构。

[单选题]What is the main idea of the passage?

Multitasking often leads to efficiency decline.