Jawaban:

rumus present perfect (PP) = Subject + Have/Has + Verb-3.

rumus present cont (PC) = subject + to be + Ving

1. Mereka membaca buku

PP = they have read a book (+)

they haven't read a book (-)

PC = they are reading a book (+)

they are not reading a book (-)

2. Budi tidur dikelas

PP = Budi has slept in the classroom (+)

Budi hasn't slept in the classroom (-)

PC = Budi is sleeping in the classroom(+)

Budi is not sleeping in the classroom (-)

3. kamu menulis surat

PP = you have written a letter(+)

you haven't written a letter(-)

PC = you are writting a letter(+)

you are not writting a letter(-)