My grandfather is always thinking for others. In other words, he is always ____.

That way of living is_______ to people in this small part of the country.

Although he is old, he’s very          . However, when he was young, he was very lazy.

Though he was born and brought up in Australia, he can speak ______ Chinese. 

It is rather ______ that we still do not know how many species there are in the world today.