for

of

in

to

If I had had your address, I would have sent you a Christmas card

If I hadn’t had your address, I wouldn’t have sent you a Christmas card.

If If I didn’t have your address, I would send you a Christmas card.

If I had your address, I would have sent you a Christmas card.

expensive

unreasonable

modest

costly

I haven’t gone on a family vacation for three years.

I have gone on a family vacation for three years.

I didn’t go on a family vacation was three years ago.

I haven’t gone on a family vacation since three years.

was driving

very

and

what

decisively

decision

decisive

indecisive

felt upset

became angry

stayed calm

said nothing

Water pollution

Human and environment.

Awareness of conservation.

Resources for the future.

Successes and failures in modern cities

Successful cities of the future

Sustainable cities: Can we build them?

The problems of city life

heard

appreciated

musical

dramatic