类似于C，一般用'\'作为转义字符
如'escape using "\\"' 将显示 escape using "\"
'That\'s right' 显示 That's right
#{expr}序列把任何Ruby代码的值放入字符串中
"Seconds/day: #{24*60*60}" 得到 Seconds/day: 86400
"#{'Ho! '*3'}Merry Christmas!" 得到 "Ho! Ho! Ho! Merry Christmas!"
"This is line #$." 得到 This is line 3
进行插入替换的可以是一条或多条语句，如：
irb(main):007:0> puts "now is #{def the(a)
irb(main):008:0" 'the '+a
irb(main):009:0" end
irb(main):010:0" the('time')
irb(main):011:0" }for all good..."
now is the timefor all good...
=> nil
irb(main):012:0>
