Trees on the hills can stop the rains from        away the soil.

. --- I usually go there by bus. It is very crowded.   --- _______ there by train? It’s fast and cheap.

— Should people stop using their cars and start using public transport?— __________. The roads are too crowded as it is.

When ______ comes to research into heart disease and its effects on the body, we do not have adequate substitutes for the use of animals.

 —Dear, I can find a better job if I go to Germany, maybe.— Don’t be silly. ________, you know.