раскройте скобки.употребляя глаголы в present perfect past simple past continuous или past perfect
1) columbus (not to know) that he (to discover) america
2)i already (to read) five english books.
3)he (to discuss) the problem with a lot of people before he (to take) a decision.

thank)

1) columbus didn`t know that he had discovered america2)i have already  read five english books.3)he had discussed the problem with a lot of people before he took a decision.