单项选择题
Our children and grandchildren will ______ if we don't look after our planet.
单项选择题 Anyone, rich or poor, old or young, sick or ______ , can pick up a hobby.
单项选择题 By the sixth century AD, when few Europeans could read, the Chinese ______ paper.
单项选择题 It isn't quite ______ that he will be present at meeting.
