a. The time machine will be shown to the public when they finish it.

b. It's very important to keep the environment clean.

c. It's boring to see this film.

d. It's not easy to understand these lessons.

e. Old car tires are recycled to make shoes and sandals.

f. The bottles are cut into small pieces.

g. The small pieces are mixed 

h. The mixture is heat into pasty liquid.

i. The liquid is blown into new bottles.

j. Used plastic things are recycled to save natural resources.

k. We are ready to clean the environment.

l. It is very difficult to keep people from littering.

m. She is not pleased to empty the kitchen garbage.

n. It is lucky to being able to live in a clean environment.

o. They are surprised to hear about the plan to collect the used boxes.

- $Answered$ $by$ $thieukhue$ -

a) The time machine will be shown to the public when they finish it.

b) It's very important to keep the environment clean

c) It's boring to see this film.

d) It's not easy to understand these lessons

e) Old car tires are recycled to make shoes and sandals

f) The bottles are cut into small pieces 

g) The small pieces are mixed with certain chemicals

h) The mixture is heat into pasty liquid

i) The liquid is blown into new bottles.

j) Used plastic things are recycled to save natural resources.

k) We are ready to clean the environment

l) It is very difficult to keep people from littering

m) She is not pleased to empty the kitchen garbage

n) It is lucky to live in a clean environment.

o) They are surprised to hear about the plan to collect the used boxes.