搜题请搜索小程序“爱下问搜题”
问题 选择题

如图所示，质量为M的物体靠在粗糙的竖直墙上，物体与墙面的动摩擦因数为μ．现用垂直于斜边的推力F作用于物体上，物体保持静止状态，则物体受到墙面的摩擦力为（　　）

A．μMg

B．μFcosθ

C．Mg+Fsinθ

D．μFsinθ

答案

对物体受力分析如图所示，由平衡条件可得f=Mg+Fsinθ，所以C正确ABD错误．

故选C．

改错题
此题要求改正所给短文中的错误。对标有题号的每一行作出判断：如无错误，在该行右边横线上画
一个勾（√）；如有错误（每行只有一个错误），则按下列情况改正：
此行多一个词：把多余的词用斜线划掉，在该行右边横线上写出该词，并也用斜线划掉。
此行缺一个词：在缺词处加一个漏字符号（∧），在该行右边横线上写出该加的词。
此行错一个词：在错的词下画一横线，在该行右边横线上写出改正后的词。
注意：原行没有错的不要改。
    I went to see the film after supper. On my way to the      
cinema, I met the English woman, who lost her way.          
I gave up the chance see the film and took her to her       
hotel. While go there, I told her about great changes      
that had been taken place in the past few years           
and she she had told me something about her country.      
Although I missed the film, but I still felt very happy, for 
I had not only helped her out of trouble but practised     
my spoken English. If I had not worked hard on            
English, I would not have been able to help him.          		1.________       
2.________    
3.________     
4.________     
5.________                                                
6.________      
7.________    
8.________     
9.________     
10.________  
查看答案
单项选择题

输血相关性移植物抗宿主病的临床表现不包括（）。

A.高热，且热型不规则

B.有消化道症状包括恶心、呕吐、腹泻和腹痛

C.少尿

D.发热1～2天后，面部和躯干皮肤出现红斑和丘疹

E.骨髓抑制致全血细胞减少，出现贫血、出血
查看答案