English (Basic) - Lesson twenty six

Too bad' means regrettable or unfortunate.  When using it in a sentence you are expressing a concern or regret for what has taken place.  The topic being discussed could have happened to you, the person you are talking to, or someone or something else.

Here are some examples:

"It's too bad that she lost her job."
"It's too bad that you have to go."
"It's too bad that I found out about it."
"It's too bad we will not be there on time."
"It's too bad that tickets are all gone to that concert."
"It's too bad that it is supposed to rain."
"It's too bad that she got hurt."
"It's too bad that my work has to lay off people."
"It's too bad that you do not understand."

 You could have + (past participle)
 You could have + (past participle)
Using 'could have' you are speaking about something that was, should be or would be. You are stating that they had other options that could have been chosen.

Here are some examples:

"You could have completed it sooner."
"You could have blown your chance."
"You could have done better on your exam."
"You could have given me more time to get ready."
"You could have heard that from someone else."
"You could have sent that package first class."
"You could have slept in a little longer."
"You could have written him a letter."
"You could have thought of something to do."
"You could have upset her by saying that."
  Source:http://www.manythings.org/elllo/