Put the verb into the correct form (past simple or present perfect). 1. i . . . (to see) her recently. she ... (to change) a lot. 2. john . . . (to move) to a new house three days ago. 3. she . . . (to work) at this office for 10 years. now she ... (to decide) to retire. 4. i don’t think i ... (to know) your wife. i . . . (not to meet) her. 5. john . . . (to see) susan last week but he . . . (not to see) her since. 6. this african boy . . . (never to see) snow. 7. it . . . (to happen) when i was out. 8. she ... (to take) the envelope, ... (to open) it and . . . (to take) a small sheet of paper out. 9. i . . . (not to see) him of late. 10. when you . . . (to see) mr brown?

Here are the correct forms of the verbs for each sentence:

1. I have seen her recently. She has changed a lot.
   • Use Present Perfect for "recently" and to describe a present result of a change.
2. John moved to a new house three days ago.
   • Use Past Simple because "three days ago" is a specific finished time.
3. She has worked at this office for 10 years. Now she has decided to retire.
   • Use Present Perfect for an action continuing up to the present and for a recent decision.
4. I don’t think I know your wife. I have not met (or haven't met) her.
   • The first verb remains in the present; the second is Present Perfect because it refers to "any time up to now."
5. John saw Susan last week but he has not seen (or hasn't seen) her since.
   • Use Past Simple for "last week" and Present Perfect for "since."
6. This African boy has never seen snow.
   • Use Present Perfect for life experience ("never").
7. It happened when I was out.
   • Use Past Simple for a specific event in the past.
8. She took the envelope, opened it and took a small sheet of paper out.
   • Use Past Simple for a sequence of completed actions in a story.
9. I have not seen (or haven't seen) him of late.
   • Use Present Perfect with the phrase "of late" (meaning recently).
10. When did you see Mr. Brown?
    • Use Past Simple for questions starting with "When" referring to a specific point in time.

Would you like me to provide the specific grammar rules for when to choose between these two tenses?