4Complete these sentences with the words in the box. You do not need all the words. adware biometric scanning browser hijacker encryption
firewall hacker malware attack spyware Trojan

19A(n) is someone who tries to break into a computer system.
20A program which is usually free but contains a virus is called a(n)
21An effort to get unauthorised access to a computer is called a(n) .
22A(n) is software that replaces the user’s search engine with its own.
23 blocks authorised access.
24Software that sends information about the use of a computer system is called .
25 is one way to make sure that only authorised people access the network.
26 is software that automatically plays commercials on a computer.

Cначала по заданию: это не Present Perfect. В примерах приведено Past Simple.Поэтому постараюсь отвечать на вопросы двумя предложениями: сначала past simple, после Present Perfect.
P.S.: не забывай ставить "лучшее решение"
1)Did you get up early yesterday? No, I didn't. I have not sleep enough yet.
2)Did you go to the country last summer? Yes, that was wonderful. I've visited my grandma.
3)In what subjects did you take exams before you entered the Institute? It were math and english. I've done an excellent job in my studying.
4)When did you become a student? It was at 2010.
5)When did you see the dean of your department last? I saw him yesterday.
6)When were you born? I was born at 1998.
7)Where were you last winter? I was at Moskow.
8)How many books did you read last year? I read a lot last year. I've done War and Peace, for example.
9)Who was the first to come to the Institute yesterday? Our dean was the first to come.
Не везде возможно, вообще, создать Present Perfect.

ответ: 1: be/was/been, become/became/become, begin/began/begun, blow/blew/blown, break/broke/broken, bring/brought/brought, buy/ bought/bought, come/came/come, catch/caught/caught, choose/chose/chosen, do/did/done, drink/drank/drunk, drive/drove/driven, eat/ate/eaten, fall/fell/fallen, forget/forgot/forgotten, give/gave/given, go/went/gone, grow/grew/grown, hear/heard/heard, keep/kept/kept, know/knew/known, leave/left/left, lose/lost/lost, make/made/made, meet/met/met, pay/paid/paid, read/read/read, rise/rose/risen, run/ran/run, see/saw/seen, send/sent/sent, show/showed/showed, sit/sat/sat, sleep/slept/slept, stand/stood/stood, strike/struck/struck, take/took/taken, teach/taught/taught, think/thought/thought, wake/woke/woken, win/won/won, write/wrote/written

объяснение:

1. yes, i have.

2. yes, i have.

3. yes, i have.

4. no, he hasn't.

5. yes, she has.

6. no, it hasn't.

7. yes, they have.

8. yes, they had.