复数： trackballs

Using a computer mouse or trackball can be a little tricky .

使用鼠标或轨迹球可能会稍微有点棘手。

Some actually felt like native games and even used the trackball for control .

有的感觉就像是老游戏，甚至要用轨迹球来操作。

To select , one needs only to press in on the trackpad just as with the trackball .

想要选择，你只要在触摸板上轻轻地按一下，与轨迹球的用法一模一样。

You can also choose to have the system keyguard disabled so you can wake up the phone by clicking the trackpad / trackball .

你也可以禁用系统的按键防护功能，这样你就可以通过点击轨迹板/轨迹球来唤醒你的手机。

After backing out of the menu , an encryption key can be selected by moving the trackball and typing characters on the keyboard .

退回菜单后，通过移动轨迹球或输入键盘上的字母选择一个密钥。