在一根很长的弦线上形成的驻波,下列对其形成的叙述,哪个是正确的?() A.由两列振幅

题型:单项选择题

问题:

在一根很长的弦线上形成的驻波,下列对其形成的叙述,哪个是正确的?()

A.由两列振幅相等的相干波,沿着相同方向传播叠加而形成的

B.由两列振幅不相等的相干波,沿着相同方向传播叠加而形成的

C.由两列振幅相等的相干波,沿着反方向传播叠加而形成的

D.由两列波,沿着反方向传播叠加而形成的

考点:一级结构工程师基础知识普通物理普通物理题库
题型:单项选择题

下列可以称为自然天体的是(  )

A.美国的军事间谍卫星

B.即将发射的气象卫星

C.呈云雾状外表的蟹状星云

D.按照航线飞行的飞机

题型:单项选择题

哪些药物可以诱发或加重重症肌无力症状()

A.地西泮,苯巴比妥类镇静剂

B.氯化钾

C.D-青霉胺

D.氨基糖苷类抗生素

E.肌肉松弛类药物

题型:单项选择题

Why play games? Because they are fun, and a lot more besides. Following the rules… planning your next move…acting as a team member… these are all “game” ideas that you will come across throughout your life.

Think about some of the games you played as a young child, such as rope-jumping and hide-and-seek. Such games are entertaining and fun. But perhaps more importantly, they translate life into exciting dramas that teach children some of the basic rules they will be expected to follow the rest of their lives, such as taking turns and cooperating.

Many children’s games have a practical side. Children around the world play games that prepare them for work they will do as grown-ups. For instance, some Saudi Arabian children play a game called bones, which sharpens the hand-eye coordination (协调) needed in hunting.

Many sports encourage national or local pride. The most famous games of all, the Olympic Games, bring athletes from around the world together to take part in friendly competition. People who watch the event wave flags, knowing that a gold medal is a win for an entire country, not just the athlete who earned it. For countries experiencing natural disasters or war, an Olympic win can mean so much.

Sports are also an event that unites people. Soccer is the most popular sport in the world. People on all continents play it — some for fun and some for a living. Nicolette Iribarne, a Californian soccer player, has discovered a way to spread hope through soccer. He created a foundation to provide poor children with not only soccer balls but also a promising future.

Next time you play your favorite game or sport, think about why you enjoy it, what skills are needed, and whether these skills will help you in other aspects of your life.

小题1:Through playing hide-and-seek, children are expected to learn to ________.

A.be a team leader

B.obey the basic rules

C.act as a grown-up

D.predict possible danger小题2:The underlined part in Paragraph 2 most probably means that games can ________.

A.describe life in an exciting way

B.turn real-life experiences into a movie

C.make learning life skills more interesting

D.change people’s views of sporting events 小题3:According to the passage, why is winning Olympic medals so encouraging?

A.It inspires people’s deep love for the country.

B.It proves the exceptional skills of the winners.

C.It helps the country out of natural disasters.

D.It earns the winners fame and fortune.小题4:Iribarne’s goal of forming the foundation is to ________.

A.bring fun to poor kids

B.provide soccer balls for children

C.give poor kids a chance for a better life

D.appeal to soccer players to help poor kids

题型:单项选择题

男,29岁,既往体健,最近2个月乏力伴全身关节痛,近2周出现皮肤成片淤斑,经常鼻出血;查体:贫血面貌,巩膜不黄,浅表淋巴结轻度肿大,胸骨压痛(++),心肺正常,腹软,肝肋下1.5cm,脾肋下2.0cm,四肢关节无红肿畸形、活动受限。上、下肢皮肤各有2处3cm×3cm大小的新鲜出血斑,无压痛,无破溃。

根据选择的检查,可考虑以下哪种疾病的可能性较大

A.多发性骨髓瘤
B.慢性肝炎
C.淋巴结反应性增生D.急性白血病
E.再生障碍性贫血

题型:单项选择题

在地下工程中管线覆土深度超过( )时为深埋。

A.1.0 m

B.1.5 m

C.2.0 m

D.2.5 m

更多题库