selectively 有选择的                        arrow keys    方向键

convenment 方便的                         character keys  字符键

alter        修改                                   function keys 功能键

carriage return  回车                        clear A of B   清除A中所有的B

linefeed      换行                               default coder 默认代码

familiar    熟悉的                              fill with 用...填充

layout     布局

the numeric keypad   数字小键盘