Living constantly in the atmosphere of slave, he became infected （） the unconscious（）their psychology. No one can shield himself（）such an influence. A: on...by...at B: by... for...in C: from...in...on D: through...with...from

Enzymes speed up chemcial reactions by... A: lowering activation energy. B: increasing the activation energy needed. C: breaking the chemical energy needed. D: stopping the chemical reaction.

Which sentences are right? A: We owe your name and address from.... B: Through the courtesy of Chamber of Commerce..., we come to know your name and address C: We have your name and address from the same trade of... D: Your company has been introduced to us by... as...