.   A: I have been working for the same company __________ two years.

since
for
in

6.   A: When I was a child, I ________ to play baseball on the school team.

was used
would
used

2.   A: What happened? Why are you so late?
      B: I know I should have come _________ but I got stuck in traffic
earlier
earliest
early

7.   A: I am interested _______ learning foreign languages.

of
in
about

3.   A: What made you decide to take up guitar lessons?
      B: ______________ to become a guitar player.

I had always wanted
I always wanted
I have always wanted

8.     A: My teachers always ________ me study hard when I was attending high school.

made
let
have

4.   A: I’d like to enter the marathon next Saturday.
      B: But you haven’t been running ______ to enter a race.
long enough
too long
enough long

9.   A:I was eating dinner when a tarantula walked across my plate.
      B: ________ disgusting experience that must have been!
How
What
What a

5.   A: You ___________ between eight and ten because I went out for dinner.

should have called
must have called
would have called

10.A: I _________ my homework when John arrived.

finished
have finished
had finished

Life without computers (11)  became has become has became unimaginable. They are designed to look after so many boring but essential tasks that we have become (12) dependent on dependent from responsible for them. But as the demands placed on computers grow, so have the number of incidents (13) including involving promoting computer errors. Computer experts warn that the traditional ways of building computer systems are not good enough (14) dealing dealt to deal with complex tasks like flying planes or maintaining nuclear power stations.

In 1889, the word "bug", meaning a mistake, entered the (15) idiom mother tongue language . For decades, a computer engineer´s job (16)has supposed to were supposed to was supposed to involve "de-bugging". For example, if a bug entered a nuclear power station, lots of lives would be (17)in danger risky misleading

However, for the last fifteen years, a growing (18)degree amount number of computer safety experts have been claiming that programmers themselves have to learn to demonstrate mathematically how safe a program is.(19)If Although Unless programmers learn to do this, we will probably just have to live with the results of computer bugs. Until that moment comes, we should follow an MIT professor´s advice:"PC users (20)would rather had better would like to take precautions by means of using legal software."