5.

a)This computer will continue to be used

b,Rubber trees began to be planted in big plantation.

d,Coca-cola will continue to be drunk in the 21st century

6,

aThe research was given up after three hours .

b,The matter should be looked.

c,You aren't spoken until someone asks you .

d,The children are being looked after by a neighbor .

7.

b,He was seen to steal your car.

c.They are being watched to work by the teacher.

d,You won't be let to do that silly thing again.

e, Children aren't made to work hard.

g,The woman was seen putting the jewelry in her bag by the detective.

h,The hostages were made to lie down by the terrorists.

8.

a,your book must be opened

b,your hat must be taken off

c,that silly thing mustn't be done again.

d,let's them be told about it.

e,I was told not to let the other see me