That a ....... remark, and it made his friend feel bad. (think)

I’m not ................... that this latest invention will make people’s lives better. (convince)

Unfortunately, the children ............ when they visited the aquarium. (behave)

I would hate to teach children. They always ................. (behave)

Important ......... research is carried out in the laboratories of the university. (science)

Some scientists fear that the environmental damage caused by global warming is ................ (reverse)

Finding a cure for the disease turned out to be much more ..................  than the scientists expected. (challenge)

Coffee shops in Europe declined in popularity in the late eighteenth century due to the greater ......... of tea,. (consume)

The results were .......... good. (relative)

They kept in touch .......... for years. (regular)

The bad weather affected our ........ of the game. (enjoy)

It is becoming .......... obvious that politicians only think in terms of four years ahead, which is proving to be disastrous for the environment. (increase)

The experiments we did in the laboratory last week were all very ............... . (succeed)