<span>to be was/were been
to have had had
to mean meant meant
to learn learnt learnt
to become became become
to bring brought brought
to know knew known
to think thought thought
to buy bought bought
to play played played
to take took taken
to do did done
to begin began begun
to give gave given
to make made made
to keep kept kept
to get got got
to read read read
to show showed shown
</span>
1.Many people had an opportunity to use computers
2.There was no doubt that computers were solving so problems very quickly
<span>3.Instructions directed the operation of a computer
</span>
1) didn't see
2) where you going?
3) visited
4) had
5) did you call
6) don't know
7) we discussed this since
8) gets pregnant
9) looked
10) worked
11) collapsed
12) you visited
13) always liked
14) baked
15) played
16) breaks
17) stole
18) maked
19) thought
20) was
21) likes
22) will be
23) will celebrate
24) didn't decide
25) just invite
26) Will you come?
27) working
28) will begin
29) leaving
30) enjoy
Is
Aren't
Are
Isn't
I'm not
Are
1 did
2 did
3 do
4 does
5 do
6 does
7 do
8 does
18B 19A 20D 21D 22D 23C 24B 25B 26C 27B 28B 29B 30B 31A 32B 33D 34C 35A 36D