Present Perfect Tense : Unit 18, I Have Done (present perfect) and I did (simple past)

A.      Sometimes you can use the present perfect or the simple past (“I have lost” or “I lost,”
“he has gone” or “he went” “they have seen” or “they saw”, etc.) :

-          “Where’s your key?”   “I’ve lost it.” Or “I lost it.”

-          “Is Jack here?”    “No, he’s gone home.”   Or “He went home.”

B.      With a finished time (for example : yesterday / last week / in 1998 / six months ago), you can only use the past (not the present perfect) :

Do not use the present perfect (have done/have lost/have been, etc.) with a finished time :

-          I saw Jack yesterday. (not “I have seen Jack yesterday.”)

-          Where were you last night? (not “Where have you been last night?”)

-          We didn’t take a vacation last year. (not “We haven’t taken.”)

-          I got up at 7:15. I washed, got dressed, and then I had breakfast.

-          William Shakespearce (1564-1616) was a writer. He wrote many plays and poems.

(not “. . . has been a writer . . . has many written many plays.”)

               Use the simple past to ask When? Or What time? :
                                -When did they arrive ? (not “When have they arrived” )

C.      Compare : 

For the present perfect, see units 14-16.     For the simple past, see units 9-10