Water can absorb and give off a lot of heat without big changes in temperature, thus creating a __________ environment. 

Tired of the president’s _______ speech, the people _____ at the back began to play with their mobile phone.

My grandfather is always thinking for others. In another word, he is always ________.

Taking exercises is _______to your health.

The girl looked at me with a ______expression. Maybe the problem was quite _____.