鼓风机是利用动能转换为(),实现空气的排出的。(A)势能 (B)电能 (C)压能 (

题型:单项选择题

问题:

鼓风机是利用动能转换为(),实现空气的排出的。

(A)势能

(B)电能

(C)压能

(D)风能

考点:热注运行工考试中级热注运行工中级热注运行工题库
题型:单项选择题

根据短文内容,回答问题。

      It's sunny today. My friends and I are playing on the beach (沙滩). It's a very beautiful place (地方). The

water is clean and blue. We are having a good time. Many birds are flying over the sea. Some are standing on

the rock (岩石). Many people are swimming. Some boys are playing football. Some people are lying (躺) on

the beach. Mary is sitting on a chair and drawing a picture. John is taking pictures of his friends. And I'm

sitting on a rock and writing to you! What are you doing now? I hope I can get your letter soon.

                                       Best wishes,

                                         Tim

1. What's the weather like today?

__________________________________________________________

2. Where are Tim and his friends?

__________________________________________________________

3. Can they see birds?

__________________________________________________________

4. Is Tim playing football on the beach?

__________________________________________________________

5. What is John doing?

__________________________________________________________

题型:单项选择题

数列{an}中,a1=1,且点(an,an+1)在直线l:2x-y+1=0上.

(Ⅰ)设bn=an+1,求证:{bn}是等比数列;

(Ⅱ)设Cn=n(3an+2),求{Cn}的前n项和.

题型:单项选择题

离子反应、复分解反应、置换反应、氧化还原反应之间可用集合关系来表示,其中正确的是 [ ]

A.

B.

C.

D.

题型:单项选择题

Lucy knew nothing about it _____ her sister told her.[ ]

A. because

B. until

C. if

D. since

题型:单项选择题

汽车的故障可分为轻微故障、一般故障、严重故障和()故障。

A.功能

B.参数

C.报废

D.致命

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