单项选择题The possible causes of the worldwide increase in kidnappings are all the following EXCEPT that ______.
单项选择题According to the author, what is the central problem facing biological researchers today
单项选择题in the sentence In truth, Verne was neither a scientist nor an engineer: he was simply a writer and a very prolific one. , the word prolific probably means ______.
单项选择题In the idiom in good feather , we change good into high, full without changing meaning. This change of constituent is known as ______.
单项选择题Three British soldiers were killed in ______.