[填空题]When Earth began to take solid form, there was no water or ice on its surface because ______.

[填空题]When Earth began to take solid form, there was no water or ice on its surface because ______.

[单项选择] In these times, when our form of government is being criticized by people of’’ many different persuasions, it is important that we understand the principles on which our society was founded. Too often these principles are disregarded by the very people who are most vociferous (大声叫的) in defending the country against criticism. Basic to our democracy is belief’’ that truth can only be arrived at through a free interchange of ideas. Freedom of speech is one of our most cherished values. Nevertheless, with a total disregard of the principles of democratic fair play, the average citizen is apt to hurl harsh accusations in an attempt to silence anyone who may not agree with him. Too many citizens understand democracy only as a slogan and have no real concept that democracy in practice means we must tolerate the expression of unpopular ideas. Our list of deadly sins should be revised to include the misrepresentation of principles to gratify one’’s personal spite or vanity, the betrayal
A. Objective interest
B. hesitant acceptance
C. pessimistic disillusionment
D. enthusiastic endorsement

[简答题]A change of state from a solid to a liquid form requires heat energy.