If you don’t communicate your ideas ______ others, how can they understand you?[ ]

Everybody was touched __________ wordsafter they heard her moving story

Peter, where did you guys go for the summer vacation?—We ____ busy with our work for months, so we went to the beach to relax ourselves

cannot smile like a child, __________ a child smiles with hiseyes, while a man smiles with his lips alone.

______rise in carbon dioxide is causing _______ steady increase in global warming.