6. Manhattan is the right place to see the famous American tall buildings, we know them as .

Manhattan is the right place to see the famous American tall buildings, we know them as skyscrapers.

1. we have finished all our homework.

  2.he has visited us many times  

  3.she has returned my book at last

  4.i am afraid that i have lost my car keys.

  5. we have been in mexico many times.

  6. i have studied this exercise before.

  7. we have learned many new words in this course.

  8.my family has been to montreal.

  9. i have heard that story before.

  10.we have lent money to them several times.

  11.mr. petridis has gone to south america to work.

  12. his uncle has taught computer science for years.

  13. she has seen that movie three times.

14. he has make and lost several fortunes.

  15. kelly has tried that recipe many times.

  16.he has begun to understand what alice wants .

  17. the flowers have grown very high.

  18. they have been in acapulco many times.

  19. dick has visited them in mexico twice.