单项选择题
A potential problem which might be caused by the use of an artificial nose is ______ .
单项选择题 The examples of the Challenger and Chernobyl cited by the author serve to show that ______ .
单项选择题 The word "seminal" in the first paragraph means " ______ ".
单项选择题 According to the author, the introduction of the computer is a revolution mainly because ______ .
