shell scripting and programmming

Shell Programming and Scripting
1

hi ,

i was trying a small script in sed as my main motive is to apppnd a sentence before a line and after a line.

e.g this is the sentence which is present in many files and i want to append 2 more sentences in this sentence of mine.

tanvi is good girl

the result should come out as

here is the introduction
tanvi is a good girl
she is very good at speaking

the sentence given above is not independent in some files.....how do i grep this sentence and add and append using sed command as both are editors.

please give your suggestion

2 
sed '/tanvi is good girl/{
i\
here is the introduction
a\
she is very good at speaking
}' INPUTFILE