15．Congratulations on selecting our wireless mighty mouse．The mouse is of high quality．Only the scroll ball is visible at first glance，but it is actually a four-button mouse．At both sides，there are a couple of force-sensing buttons which can be programmed according to your need．
Setting up the Wireless Mighty Mouse
Put the batteries in the mouse first．Then pair the mouse and the computer．Setting up the mighty mouse is simple．You just need to install （安装） the software and turn the mouse on for it to get detected by the computer．
Using the Wireless Mighty Mouse
The mighty mouse has laser （激光） tracking technology，so you can use it on most surfaces．Another new invention is the 360-degree scroll wheel．It is a multi-directional scroll wheel that allows you to scroll in all directions．The left and right buttons require just enough touch pressure to accept the input．Once you have set in up to your comfort，it functions smoothly without any problems．You can use either the left or the right button to click，doubleclick，and drag items．Either button can also be used to display an item's short-cut menu．You can assign a function to the side buttons and the scroll ball，which also function as a button．
Cleaning Your Mouse and Scroll Ball
Use a cloth that's been lightly moistened （湿） with water to clean．Don't get moisture in any openings．If your mouse stops scrolling or if scrolling becomes rough，clean the mouse scroll ball．Turn the ball while cleaning for complete coverage．
56．You have toDbefore setting up the mouse．
A．turn the scroll ball slightly
B．clean the mouse with a cloth
C．check the software in the mouse
D．connect the mouse and the computer
57．What can we learn about the wireless mighty mouse？A
A．Its scroll wheel can move in all directions．
B．Different buttons have different functions．
C．Side buttons are more useful than left and right buttons．
D．Only the right button can display an icon's short-cut menu．
58．The passage is probably taken from a （an）B．
A．textbook
B．instruction
C．research report
D．scientific essay．
